Alexander Albon suffered a heavy crash in second practice at the Bahrain Grand Prix, leaving his Red Bull career hanging by a thread.
The British-Thai driver is trying to prove to Red Bull that he deserves to be kept on for 2021.
But his crash, in which he was uninjured, was the latest in a series of incidents that are undermining his case.
World champion Lewis Hamilton was fastest from Red Bull’s Max Verstappen.
Albon lost control at the final corner when on his qualifying simulation run, sliding wide, over-correcting the car and then flicking back the other way into the barriers, wiping out the right-hand side of the car and giving the team a long repair job overnight.
At the time, he was 0.7 seconds slower than team-mate Max Verstappen and trying to improve.
The incident followed spins during the past two races in Turkey and Italy, both times when he was running in a strong points position.
Red Bull have said that they want him to earn the drive, but insist they have not yet made a decision on whether to plump for a more experienced driver from outside the Red Bull programme, including either Sergio Perez or Nico Hulkenberg.
“[I’ve] had a few of them so used to it,” said Albon. “I should have pulled out of it really. I was a bit surprised by the lack of grip. Just one of those things. Not fun but all good.
“I did back out, but not enough. When you have one tyre on the Astro and one on the grip, that’s when the tank-slappers happen.”
The way the session developed, with teams on different programmes, and two red flag periods, one for Albon’s crash and one immediately after the restart because a dog was loose on the circuit, meant it was hard to get a definitive read on overall competitiveness.
Hamilton’s fastest time was just over 0.3 seconds faster than Verstappen, with the Briton’s team-mate Valtteri Bottas 0.018secs behind the Dutchman.
Racing Point’s Sergio Perez was fourth fastest, from Renault’s Daniel Ricciardo, Alpha Tauri’s Pierre Gasly and McLaren’s Lando Norris.
Ferrari’s Charles Leclerc, in a close fight with Perez and Ricciardo for fourth in the championship, was down in 14th on a day when the Italian team appeared to struggle for pace, and the drivers with the car. Team-mate Sebastian Vettel was 12th quickest.
Both sessions were influenced by tyre supplier Pirelli handing the teams 2021-specification tyres, designed with a more robust construction to run in both sessions.
Having to use two sets per driver meant the teams’ programmes diverged more than usual and put many out of sync with each other.
Hamilton, fresh from clinching his record-equalling seventh world title at the last race, was also fastest in the first session, with Bottas second and Perez third.