Charles Leclerc signs off with the fastest time of the week as speculation over the true form of the Ferrari continues.
As was the case with the majority of drivers in action this morning, having to hand over to their teammates for this afternoon's final session, this was the last chance they'll have to drive their cars before the race weekend kicks off next Friday.
If Thursday was FP1 and Friday FP2, today should be qualifying, though the unrepresentative conditions, since qualifying and the race take place much later in the day, actually mean that this morning is FP3 and this afternoon/evening qualifying.
Other than Russell's hydraulics issue yesterday, the main issue for Mercedes is understood to be a lack of downforce at the front, while Ferrari is claimed to be eating tyres.
Other teams appearing to be on the back foot are Alpine and McLaren, while Aston Martin is said to be the big surprise of the test.
Asked about the speculation, Frederic Vasseur was giving nothing away, but played down the negatives.
"So far, so good," he told Sky Sports. "A test is always intense, but it's okay."
Asked where he thinks the team stands, he replied: "It's very difficult to have a clear picture because we are a bit blind on the others, but we have some room for improvement...
"For sure we are in the top 10," he laughed.
Just minutes into the session the red flag was waved after a sensor strap fell from Perez' Red Bull. The Mexican, along with Alex Albon and Valtteri Bottas is on duty for the whole day.
While much has been made of the early conclusion to George Russell's programme on Friday, after his Mercedes suffered a hydraulics issue, Toto Wolff subsequently seen in deep and meaningful conversation with his senior staff and drivers, the Briton was keen to play down fears that the German outfit is on the back foot, also dismissing claims that the bouncing that compromised the W13 has returned.
"So far, from what we've seen the bouncing is definitely more under control than this time last year, that's for sure," he told Sky Sports.
"Definitely a lot of improvements in certain areas," he added. "The car is feeling nicer to drive, but at the end of the day there's only one thing that matters and that's the lap times on the time sheet.
"It was a pretty smooth test, then unfortunately we had the issue in the afternoon, so we lost a lot of running. But I think we've uncovered some interesting things in the data that hopefully will find us some more lap time, so you've got to take the positives."
As Hulkenberg quickest (33.690) ahead of Piastri, Russell and Drugovich, the Mercedes driver suggested that the race schedule this year could impact the teams' various upgrade programmes.
"When you look at the calendar as a whole, we've only got five races in the first two and a half, three months," he said, "whereas at the end of the season, you've probably got 10 or 11 in the same time span.
"This season is going to be won and lost midway to the end of the season, it's not going to be won or lost in the first five races.
"As much as we want to go out there and win next weekend, and we're going to be giving it everything to achieve that, we know that it's more important that we've got the right car in the right window come race six onwards, because that's where the big points are going to be won."
At which point he went quickest with a 33.685.
Oscar Piastri had the dubious honour of the first 360 of the week when he spun at Turn 10, while Perez, Russell and Leclerc battled for the top spot.
As Drugovich had a change of rear wing, Leclerc consolidated his position at the to of the timesheets, though shortly after he too opted to change his rear wing,
Having incurred a DRS issue with the prototype rear wing the youngster returned to the original, promptly having a major twitch in Turn 2.
Meanwhile, at McLaren, where Piastri had just 25 laps on the board, the team was working on the wheel brows on the MCL60, which have been an issue all week. The problem, whereby they will not remain in position, first appeared on Thursday and since then the team has had to resort to using glue and tape to try and keep them in position.
"The team is currently conducting some temporary strengthening work on the front winglets to ensure we can complete today's running,” said the Woking outfit. "It's a very minor issue that will be permanently fixed for the Grand Prix next weekend.”
Minor or not it was costing precious track time.
A gearbox issue on Valtteri Bottas' Alfa Romeo brought out the second red flag of the day, and shortly after the session resumed Russell made a move on Leclerc heading into Turn 1. The Ferrari driver appeared to block the Mercedes causing the Briton to gesture. The Ferrari subsequently re-passed the Mercedes, while Russell had previously made a similar move on Hulkenberg.
It wasn't much, but at tests we'll take any action we're offered.
The session ended with the usual VSC check and then a red flag restart, for which only Russell and Piastri appeared.
With 685 laps completed this was the busiest morning thus far, de Vries having completed the most (87) and Piastri (44) the least.
While it was a quiet morning for Perez - who continues this afternoon, - Verstappen has already shown us what the RB19 can do.
Leclerc topped the morning timesheets, edging out Russell by 0.418, but again it was the pace of the Aston Martin - in Drugovich's hands no less - that really impressed.
Williams continues to look good, as does Haas, while McLaren, AlphaTauri and Alfa Romeo all clearly have work to do.
Check out our Saturday gallery from Bahrain, here.