Oscar Piastri’s running for McLaren was significantly curtailed by a technical issue on Thursday as the penultimate day of Formula 1’s first 2026 pre-season test at Barcelona produced a sharp contrast between setbacks for some teams and encouraging mileage for others.
The behind-closed-doors shakedown at the Circuit de Barcelona-Catalunya is providing the grid with its first real-world running under the sport’s all-new power unit and chassis regulations, and while Mercedes and Ferrari continued to log heavy mileage, McLaren and Aston Martin both endured disrupted days.
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McLaren was back on track on Thursday after reigning world champion Lando Norris debuted the MCL40 earlier in the week, with Piastri taking over driving duties. However, the Australians’ programme was cut short when a fuel system issue halted progress during the afternoon session.
As a result, McLaren completed just 48 laps across the day — more than 100 fewer than both Mercedes and Ferrari — limiting the team’s ability to execute its planned test programme.
“Unfortunately, a few issues today,” Piastri said afterwards. “We had a fuel systems issue which cut our day a bit short, but I know the team is working really hard to get that fixed and get us back out for as many laps as we can tomorrow.”
The interruption left Piastri spending much of the afternoon in the garage while engineers worked to diagnose and resolve the problem ahead of the final day of running.
Those troubles stood in stark contrast to the continued momentum at Mercedes, which used the last of its three permitted running days at the five-day event to add another substantial mileage haul. Widely tipped within the paddock to begin the new rules era at the front of the grid, the Silver Arrows once again looked assured as Kimi Antonelli and George Russell shared driving duties.
Antonelli set the pace in the morning session with what was then the fastest lap of the test, before Russell raised the bar further in the afternoon. The Briton posted a 1:16.445, ending the day more than half a second clear of his team-mate and nearly two seconds ahead of the rest of the field.
In total, Mercedes accumulated 167 laps on Thursday, bringing their testing allocation to a close with what many rivals privately regard as a highly impressive start to 2026 preparations. While lap times at this stage should be treated cautiously — particularly given Mercedes’ programme appears further advanced than some competitors — their consistency and reliability have stood out.
Ferrari also enjoyed a productive day after a wet-dominated debut earlier in the week. Lewis Hamilton ran in the morning before handing over to Charles Leclerc in the afternoon, with the pair combining for 174 laps.
Hamilton described Ferrari’s running as an improvement over last year’s pre-season and labelled the mileage he achieved on Thursday as “amazing”, while Leclerc finished the day third overall on the timesheets behind the two Mercedes cars.
Elsewhere on the grid, Racing Bulls and Cadillac were also in action. Racing Bulls became the only team apart from Mercedes to fully use their allotted running time ahead of Friday, with Arvid Lindblad and Liam Lawson both completing solid programmes. Sergio Perez handled driving duties for Cadillac, logging 66 laps as the American manufacturer continues its early learning curve.
Aston Martin finally takes to the track — but briefly
The other major talking point of the day was Aston Martin’s long-awaited first appearance at the test. After confirming earlier in the week that they would miss the first three days of running while final preparations continued, the team managed to get the AMR26 out of the garage with just over an hour of running remaining.
Lance Stroll completed an initial installation lap before completing four further slow-paced tours. However, on his fifth lap, the car came to a halt in the final sector and was brought to a stop in the run-off area near the pitlane entry.
The stoppage triggered the only red flag of the day and effectively ended Aston Martin’s run. There was no immediate explanation for the issue, but the team hopes it is a minor problem that can be rectified overnight, allowing a full day of testing on Friday.
Despite the limited mileage, there remains considerable intrigue surrounding Aston Martin’s 2026 challenger. The AMR26 is the first car produced under the heavy influence of Adrian Newey, following his arrival as team principal — a designer whose work was central to Red Bull’s dominance at the start of the previous regulations cycle.
With Williams missing the entire Barcelona event after failing to complete their car in time, seven teams have now completed two days of running and are expected to finish their allocations on Friday. Aston Martin will be aiming to make up for lost time, while Red Bull is also due back on track after being sidelined for two days following Isack Hadjar’s heavy crash in wet conditions on Tuesday.
Max Verstappen is among the drivers expected to run on the final day as teams look to gather as much data as possible before development freezes tighten under the new rules.
F1 2026 Pre-Season testing: Unofficial lap times from Day 4 in Barcelona
| Pos | Driver | Team | Time | Laps |
|---|---|---|---|---|
| 1 | George Russell | Mercedes | 1m16.445 | 78 |
| 2 | Kimi Antonelli | Mercedes | 1m17.081s | 90 |
| 3 | Charles Leclerc | Ferrari | 1m18.223s | 83 |
| 4 | Oscar Piastri | McLaren | 1m18.419s | 48 |
| 5 | Arvid Lindblad | Racing Bulls | 1m18.451 | 47 |
| 6 | Lewis Hamilton | Ferrari | 1m18.654s | 87 |
| 7 | Liam Lawson | Racing Bulls | 1m18.840 | 64 |
| 8 | Sergio Perez | Cadillac | 1m21.024 | 66 |
| 9 | Lance Stroll | Aston Martin | 1m46.404 | 4 |
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