Drafted in at the eleventh hour in an attempt to help improve the team's qualifying form, Sebastian Vettel was the third busiest driver today, completing 103 laps on his way to posting the fastest time.

"I think it is a unique chance having the opportunity right after the GP to test at the same track, more or less on the same conditions," said the German. "Saturday we struggled a bit so today we tried some stuff. We needed to have a good look at it, but this is not the only thing we were here for. For sure we tried to cover as much as possible in one day.

"I think Monaco should be a strong track for us," he continued, looking ahead to the next race, "last year we were very competitive there. Now we have improved the car in the areas you need for that GP so I think it should help.

"Here in Barcelona we were as competitive as expected, with the exception of Saturday. Now we are not in the best position, we are not the favourites going to Monaco either, as the favourites remain Mercedes, but we try very hard and if there is a chance to win we'll try to win. We go step by step, not looking too far ahead. I'm convinced that the chance is there."

Having only completed four corners on Sunday, it was inevitable that Nico Rosberg would be the busiest driver, the German completing 119 laps on his way to posting the second best time, just 0.117s off Vettel's best.

The German emerged for his first run at 09:00, completing 54 laps before the lunch break and a further 65 laps in the afternoon.

Today's programme focused on suspension and setup work using the medium compound tyre, in addition to powertrain analysis.

"It's good to be back in the car," said Rosberg. "I learned a lot and we made good progress - which is really important, as it's my only test day for the whole year, so I needed to make the most out of it and try to learn as much as possible.

"We did some suspension and setup work - just a few different small bits. I'm looking forward to the rest of the season - but my focus right is now on Monaco. We'll have to keep an eye on our opposition as always but I'm feeling confident and aiming for another win."

Third quickest was Jenson Button, the Briton, who finished ninth on Sunday completing 86 laps.

It was a good day for Haas, which had Romain Grosjean on duty. The Frenchman, who suffered a brakes issue on Sunday finishing fourth quickest, 0.662s off the pace.

Pascal Wehrlein finished an impressive fifth, just 1.077s off the pace as he completed 86 laps in the Manor.

"Today has been a positive day for us," said the German. "We worked through a pretty big list of items to evaluate the new developments and also did some runs on the Supersoft later in the day. Obviously we didn't run that tyre over the race weekend so it was interesting to have the comparison against the other teams with our updated package. For me it will be nice to focus on Monaco now, where I think we can have a better weekend as a result of the work we've done here today."

"We've had a good first day at what is a busy test, particularly in terms of today's programme with Pascal," added Dave Ryan. "This is a chance for us to continue the evaluation of our new developments and really get to grips with the areas where we are still a little deficient so that we can keep improving. Pascal has done a good job. As ever, his feedback has been very comprehensive and our relative pace on the Supersoft is encouraging. We look forward to giving our development driver Jordan King his first taste of the MRT05 tomorrow."

Two days after Red Bull's sensational win, Daniel Ricciardo, who finished fourth on Sunday, worked through 89 laps of the Montmelo track as the Austrian team continued its development of the RB12 ahead of the coming races.

"So far we're pretty happy with how it's looking," said the Australian. "We'll see what they find tonight but generally it was all pretty reliable and everything ran as smoothly as it could have.

"We had a few new bits on the car that we tried; I guess there will have been some images of crazy stuff attached to the car this morning! But it all went pretty well.

"It's not as exciting as a race weekend I can tell you, but we did some good stuff today. We got the important things out of the way and there's another day left for the team here. Then we have three street circuits coming up, it's going to be good fun!"

"We qualified and raced here at the weekend so for us performance is not a concern at this test," added Head of Race Engineering, Guillaume Rocquelin. "We're all about medium and long-term development of the car this week, which is why there were no performance runs today, as well a pretty conservative choice of tyres - using what we used at the weekend.

"We had a lot of different rakes on the car this morning to test a variety of components and then in the afternoon it was more about consistency.

"As I say, it's about development, not looking at the next event, so there was no temptation to bring out the ultrasoft tyres today. We had a good clean day, though. There was a minor issues with a sensor in the morning that needed repair but other than that it was a decent day's work."

Pierre Gasly, currently leading the GP2 series after the first race weekend of the season, was on duty for Toro Rosso. The Frenchman, who hands over to Daniil Kvyat for the final day, completed 78 laps on his way to posting the seventh best time of the day.

"It's always fantastic to drive a Formula 1 car and I'm happy with today," he beamed. "The most important thing was to do a good job for the team, as well as getting plenty of mileage under my belt.

"In the morning we completed aero tests and in the afternoon we focused on the car set-up. Unfortunately at the end of the day, when we were just about to go for some performance runs on soft tyres, we had a little issue, so we had to end the day a bit earlier than planned… But I'm still pleased, as we could anyhow complete many laps today, which is always important for me to gain experience.

"This is my second time driving with Toro Rosso and I have to say I felt much more confident - knowing the team and the procedures better definitely helps. It doesn't mean it's less pressure on me, as you always need to deliver and do a good job, but the fact that it's not completely new to me any more makes me enjoy the driving more. I look forward to another outing with the team hopefully in the near future."

"Last year Pierre did a good job for us in the young driver test days and he has done another excellent day for us today," said Phil Charles, the Faenza outfit's Chief Race Engineer. "We got most of the planned program completed with a large number of aero characterization runs in the morning and then a set-up program accomplished just after lunch. His runs were consistent and his feedback was concise. We were just about to ‘set him off the leash' for some performance runs at the end of the day when a systems issue stopped the car from running. We are currently looking into it - it's a pity we could not get to see what Pierre is capable of."

Check out our Tuesday gallery, here.