A plastic bag lodged inside Sergey Sirotkin's rear brakes spoiled his Formula 1 debut at the Australian Grand Prix.
Sirotkin started from 19th place on the grid and remained towards the back of the pack when he pulled off and parked his FW41 down the Turn 13 escape road.
Williams chief technical officer Paddy Lowe said: "Our provisional analysis is that a plastic bag has been collected on the circuit, completely blocking the brake cooling, so that the right rear corner caught fire and eventually failed the hydraulics circuit.
"His brake pedal went to the floor and he had to go down the escape lane.
"That was the end of his race which is very unfortunate because it was his first F1 race and what he really needed to do was get some distance behind him so he could come back for the second event with race experience our objective, which we didn’t achieve for him today."
After a tough debut weekend, the 22-year-old expressed disappointment at the result, having lost the opportunity to gain experience in race trim.
Sirotkin added: "It didn’t go as expected and I’m not even talking in terms of the results, which we obviously wanted to achieve but didn’t. I’m talking about the learning, which we didn’t get. It’s a bit of a shame and I’m quite disappointed with that because it’s not ideal and it was not the easiest weekend for me.
"It was quite important to do a good race. Preparing for the Bahrain weekend, at least I know I have a good chance so we’re looking forward. In just two weeks we’ll be back at the track and we’ll work harder than ever. I’m sure we’ll get to where we deserve to be."
