Sergio Perez quickest in upgraded Red Bull at lunch on final test day

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SAKHIR, Bahrain -- Sergio Perez set the pace on the final morning of this week's preseason test in Bahrain, making use of an updated version of the Red Bull RB18 to go 0.4s faster than any other driver so far.

The Red Bull emerged on the final day of testing with reprofiled sidepods, offering tighter packaging around the car's internals as well as a revised opening to the car's floor. Perez used a set of Pirelli's C4 compound tyres to set the fastest time as Red Bull appeared to turn its focus to chasing performance ahead of next week's race.

Perez's time was set on a single flying lap before returning to the pits as the Mexican driver cycled through Pirelli's different compounds on qualifying-style laps, including the softest C5 tyre, the quickest Pirelli tyre over one lap.

His time was 0.854s clear of Alfa Romeo's rookie driver Guanyu Zhou, who also set his fastest time on a single-lap run on the C4 compound. There was another 0.9s gap to the next fastest driver, Pierre Gasly, but the AlphaTauri driver and the other seven on track appeared to focus on longer runs rather than qualifying-style laps.

Gasly was one of the drivers who attempted a race simulation on Friday morning and found himself sharing the track with Lewis Hamilton's Mercedes, which was also on a race simulation. A race simulation is exactly what it sounds like, where teams fuel the car to the brim to attempt to run a race distance to see how the car reacts as the fuel runs down.

Hamilton and Gasly ended up going wheel to wheel at one stage, trading positions on track from one lap to the next. Hamilton was slightly further into his race sim when they came across each other on track, suggesting he would have had the advantage of being on a lower fuel load. Even so, it's hard to read anything into the battle other than that the new generation cars appear to be able to follow each other through Bahrain's high-speed corners and overtake in the low-speed sections.

McLaren was looking to make up time on Saturday morning after two days managing brake cooling issues in Bahrain. The team brought some upgrades to the track to help manage the issue, but admits it will not have a final fix ready until next weekend's opening race.

Lando Norris completed 39 laps in total - after two complete test days in the mid 50s -- as he again stood in for teammate Daniel Ricciardo, who tested positive for Covid-19 earlier this week. Ricciardo is currently isolating at his hotel in Bahrain but is expected to complete his quarantine in time for the first race next weekend.

Times at lunch:

1. Sergio Perez - Red Bull - 1:33.105 - 43 laps
2. Guanyu Zhou - Alfa Romeo - 1:33.959 - 82 laps
3. Pierre Gasly - AlphaTauri - 1:34.0865 - 91 laps
4. Carlos Sainz - Ferrari - 1:34.905 - 68 laps
5. Fernando Alonso - Alpine - 1:35.328 - 54 laps
6. Lando Norris - McLaren - 1:35.504 - 39 laps
7. Nicholas Latifi - Williams - 1:35.634 - 73 laps
8. Lance Stroll - Aston Martin - 1:36.029 - 53 laps
9. Lewis Hamilton - Mercedes - 1:36.217 - 78 laps
10. Kevin Magnussen - Haas - 1:38.616 - 38 laps