While it is not known how much fuel the Italian was running, and hypersofts weren't available to drivers over the Grand Prix weekend, his best time of 1:15.648 was still over half-a-second quicker than anything his Ferrari teammates achieved over the three practice sessions.
Though the timesheets record that the next quickest driver, Marcus Ericsson, posted a best time 2.507s down on Giovinazzi, rain in the afternoon meant that there was little further slick running and certainly not at that pace.
There were ten drivers in action however, while Haas has chosen to sit-out the test, Toro Rosso had two cars in action, one for the main in-season test and the other completing tests of prototype 2019 compounds for Pirelli. Brendon Hartley drove the test car while Sean Gelael was on duty for Pirelli.
A crash for Gelael in the afternoon resulted in the only red flag of the day, and it was shortly after that the rain began to fall.
Despite the brief interruption caused by rain, the team completed the majority of its planned programme which consisted of mechanical set-up work, testing of new aerodynamic parts, as well as runs on various tyre compounds. The collected data will now be analysed, and the team will prepare the programme for the second day of testing tomorrow.
"It was a productive day of testing," said Ericsson. "We almost completed the planned programme, with a short interruption caused by the rain that came suddenly. Thankfully, we managed to conclude the main part before the change in weather, so it didn't affect us too much. We obtained some interesting results, and tried different set-up options for the second half of the season. Now we have to analyse the results and learn from them. It was a positive way to end the first part of the season.
"Now it is time to have a small break, and to recharge our batteries for the upcoming set of races. Give it a week and I will not be able to wait until I get back in the car, though. It will be great to come back and drive on one of the best tracks of the season in Spa-Francorchamps."
"We had a lot of interesting items to test today and plenty of work in front of us," said Brendon Hartley, who completed 126 laps. "In the morning session, we completed the most laps of any team with 94 - this was actually quite punchy in the hot conditions!
"We had another busy programme to complete in the afternoon session and ended up with a total of 126 laps, but with the unforeseen weather changes we couldn't complete all of our test items. Despite the rain at the end of the day, I have to say it was a really positive test for us!"
"We had a very busy and productive first test day, running two cars," admitted chief race engineer, Jonathan Eddolls, "one for STR and one for Pirelli - which is different to our normal testing.
"Brendon was on duty driving the STR test car and carried out a very comprehensive plan, focusing on mechanical setup tests, aero work, tyre optimization, and Power Unit tests with Honda. We completed more scientific tests we normally aren't able to carry out during a race weekend due to time constraints, running various test items on the chassis side with a view of introducing those at a later date, which were quite successful.
"There was also a number of items tested on the PU, these also performed very well. We will continue our aero work tomorrow with plans to run quite a few rakes as many teams did today. Other items included a further understanding of the tyres in these extremely hot conditions; I think we've made very good progress during the Hungarian Grand Prix weekend, however, we wanted to confirm all of our findings and try to improve further. It was an extremely productive day, and there's some really positive performance items that have come out of testing which we can look forward to introducing in future races. We will run two cars again tomorrow with Brendon and Pierre sharing duties in the Pirelli car, and Sean in the STR test car."
"For the first day of testing, work focussed mainly on the chassis side," said Honda's Toyoharu Tanabe. "However, we were also able to try various new items on the PU. The morning went very smoothly, but the rain in the final 90 minutes of the afternoon meant we stopped running early. However, we were able to gather a substantial amount of data, which we will now analyse overnight with the aim of having another fruitful day tomorrow."
Lando Norris got behind the wheel of the MCL33 for the first time since the post-Spanish Grand Prix test, the youngster completing 107 laps on his way to posting the fourth fastest time of the day.
The day ran smoothly despite a couple of interruptions, which included a red flag mid-afternoon, and then a surprisingly heavy downpour 90 minutes before the end of the day's running, prompting the use of Intermediate tyres for the final few runs to evaluate the conditions.
The rest of the day was dedicated primarily to aero correlation and development over shorter runs in the morning, after which the team moved to longer runs in the afternoon before the rain came.
"It was really enjoyable to get back in the car today," said Norris, "especially as it's one year since I first made my debut.
"The first three-quarters of the day were obviously really good. I did a lot of testing; quite a few aero runs but at the same time a good amount of proper runs, so I had a good feeling for the car - until it rained! That put us back a bit, so there are some things we'll need to carry on testing tomorrow.
"It's the first time I've driven a Formula 1 car in the rain, so it was good to feel the difference from F2 to F1 in the wet. It was still tricky, but I thought it would be a lot trickier because of how much more horsepower you have in F1. At the same time, you have a lot more grip than in Formula 2, so it's just on another level, in a similar way to how it is in the dry. Cornering speeds and braking performance are much better than you'd expect in the rain, so I had more confidence than I thought I was going to have. I was a bit nervous before I went out because it got properly wet very quickly!
"I had a good feeling even in the wet, but then it dried out very quickly. I've experienced basically everything today weather-wise, and did 107 laps, so that's really positive."
"We did a lot of laps with the added bonus of some wet running for Lando," added Gil de Ferran, "so he's been able to learn about the car for the first time in these conditions.
"Lando acclimatised himself very quickly and we went through an extensive programme of test items, which has provided us with a lot of useful information. We hope for more of the same on day two, so we shall see what tomorrow brings."
At Mercedes, where a gearbox issue interrupted the run plan in the morning, the programme focused on aero rake data collection. The team also logged data on the vibration of engine and chassis components.
"It's been fantastic to get back behind the wheel of the car," said Russell. "The speed, power and downforce are just completely on another level, so as soon as I jumped in this morning I had a massive smile on my face.
"Unfortunately, we didn't quite do as many laps as anticipated owing to some rain this afternoon and a couple of small issues this morning. Nevertheless, it's been a really good day for me and I think the team learned some things, which is important. Now I'm looking forward to tomorrow."
"It wasn't the best of days for us as we only completed 49 laps," admitted Andrew Shovlin. "We had an issue with the gearbox early on that cost us some time. We were able to tick off some of the data collection test items in the remainder of the morning and early afternoon but, just as we started to get into some proper running, it began to rain.
"It's been good to see George back in the car today and he's done a good job but we had hoped to keep him a bit busier. We've got a lot to do tomorrow, and it looks like we may get some more rain, so we will review our programme tonight to make sure we can make the most of these conditions."
Hot on the heels of his superb drive from 12th on the grid to fourth place in Sunday's Grand Prix, Daniel Ricciardo was today back behind the wheel of the RB14.
Commenting on his final day in the RB14 before the summer break, the Australian said: "We did some good work today. There was a lot of long run stuff, a lot of data gathering, and we got through some set-up changes as well, so it was a pretty good day for the team. We ran with a lot of rakes and aero parts, so I know we tried a few things, but honestly I'm not too sure of the detail. I do know we used some 2019 Pirelli test tyres and that did feel quite different, so we'll see what comes of that. It was a pretty busy day and we got a lot of laps under our belt, so I don't feel too bad about saying that's me done for the moment... now it's holiday time!"
"We had a very productive test today," added Senior Projects Engineer, Jeff Calam, "during which we were able to look towards the races to come after the summer break and also towards next season. We ran some test elements aimed at 2019's car and gathered a lot of valuable information, which will certainly help with the development of the RB15. As with other teams we also had a set of 2019 Pirelli test tyres available, so all in all it was a very useful day for the long-term.
"It was also useful for the short and medium-term too, as we were also able to answer a few questions we've had about the RB14 since the last in-season test in May and the data from that will undoubtedly help us for the remainder of this season. We had some rain today, but that wasn't unexpected, so we even managed to schedule in some wet weather test items. Overall a very good day, with no reliability issues, and a lot learned."
"It has been a very productive day," said the Canadian, "and I was happy to get many more laps behind the wheel, getting more and more confident with each run.
"The majority of our programme was built around the new aero parts for 2019, based on the new set of regulations for the sport: it was interesting to feel how they worked on the car and to gather data for the team. In the afternoon we got caught out by the rain, which meant I didn't get to do the fun part - the performance runs we had planned with hypersoft tyres. I was a bit disappointed to miss out on that but that's how it happens sometimes. I am still pleased with my performance today and I am looking forward to being in the car again soon."
"It was overall a successful day," added chief race engineer Tom McCullough. "We managed to get all the aero data we set out to obtain, something that was critical for our 2019 car development.
"We had a new front wing on the car, alongside other test items and instrumentation. Nicholas didn't put a foot wrong all day - he settled straight back into the team and, as it was clear from the previous times he was in the car, he was able to do useful work from the first lap.
"The heavy rain showers in the afternoon meant we had to cut our programme short, but we still managed a solid 103 laps so we can be satisfied with our work."
Renault had a productive morning with Nico Hulkenberg at the wheel. Unfortunately, an electrical issue on the car required extensive diagnosis and time-consuming rectification meaning no running for the German in the afternoon.
"It was good to work on the car in the morning, but my afternoon was rather less productive," admitted Hulkenberg. "That's the nature of testing sometimes, and it's better to be affected by things like these at a test than during a race. My focus is now very much on recharging my batteries and coming back for Spa in top form."
"Today was the first time we ran with chassis R.S.18-04 and we did have a productive morning of aero tests and working on set-up developments from the weekend to help determine future directions," said sporting director, Alan Permane. "Unfortunately, the afternoon run plan was interrupted by an electrical issue which took a long time to diagnose and then rectify. We are looking forward to seeing Artem make his debut in the car tomorrow."
"I think in general it went well," said Oliver Rowland who posted the ninth best time of the day for Williams. "I would have preferred to get a bit more of a run at the end when the rain came in, but I can't control the weather. Everything ran to plan for the team, there was a couple of hold ups during the day but we managed to make up for that time and the mechanics did a job to get everything fixed and fitted in certain times throughout the day. From a team's perspective we gathered a lot of data and it was positive."
"It was a good day for the team," added Rob Smedley. "We had spent a long time preparing for this event, concentrating on 2019 aero regulations. The team did a good job to prepare for it and everything went more-or-less according to plan, and we collected all the data we needed.
"We brought a 2019 aero specification front end, and all of the data that we were able to collect will really enrich the 2019 programme going forward. Oliver did a great job, he got on with it, was very professional and diligent and went through all the data gathering runs. He was unfortunate with the weather at the end of the day when it started to rain, as we had just got onto a clean car, so he hasn't really put in any timed laps. But, he certainly impressed us all with his work ethic. Once we did get onto new tyres at the end of the aero testing, he did a really good job and showed good pace immediately."