It was a productive day for the team in which Vettel was one of three drivers to surpass 100 laps.
However, moving to hypersofts soon helped Vandoorne deal better with wet track and set the fastest lap.
This was most obvious at Mercedes. I assume so. Id have to assume hes going to be in the best shape possible. I think we can still understand more and understand better what's going on with more running. A late trip to the gravel at the long Turn 12 with less than two hours left of the session further truncated Red Bull's day. Not bad for a first try!
Bottas is reportedly facing criticism of having a lack of killer instincts as he is fighting once again for a new Mercedes contract extension after his current deal with the team is set to expire at the end of the upcoming season. "My mindset is really about learning as much as we can and being as consistent and diligent as you can with the laps you do get, but of course this is all foundations, building blocks for the title fight", he said. The fact he achieved it on medium tyres only made the time more impressive, offering yet another reminder of the quality of the Mercedes vehicles.
Thursday witnessed a bumper day of action as the snow and rain finally cleared with 1,101 laps racked up by the teams compared to 725 on Monday, 736 on Tuesday and just 17 on Wednesday, 11 of which were claimed by carefree two-time world champion Fernando Alonso in his McLaren. Other driver swaps for the "afternoon session" included Chalres Leclerc for Ericsson, and Lance Stroll for Sirotkin.
Red Bull's pace was still reasonable, with Daniel Ricciardo topping the first day, and he and Verstappen ending the test fifth and seventh in the combined times despite not getting a chance to run when the track was at its warmest on the final afternoon.
"But so far it's good".
Lewis Hamilton likened himself to Roger Federer as he declared he should have "no problems" in beating Sebastian Vettel to this year's Formula One world championship. Not many people would have bet on that at the start of the week!
Hamilton was ominously quick on the final day of testing, however, and the Briton also set his best time on the slower, medium tires.
Australian Daniel Ricciardo, who will be out of contract at Red Bull, and young Mercedes protege Esteban Ocon, who is now with Force India, are two strong candidates should Bottas fall short of what is required. Red Bull is a case in point.
"So theres no more excuses for sure".
A sensor problem restricted development driver Nikita Mazepin to just 22 laps on the day the vehicle launched, while reserve driver Nicolas Latifi was too ill to take up his scheduled time in the auto on Thursday.