McLaren has discovered that Lewis Hamilton's handling issues over the Japanese Grand Prix weekend were caused by a rear suspension problem.
The 2008 world champion was plagued by understeer in qualifying and the race at Suzuka, where he came home a distant fifth having started down in ninth.
Hamilton was baffled by the issue at the time, which he felt cured itself during the race on Sunday.
But speaking to reporters in the paddock ahead of this weekend's Korean Grand Prix, he said McLaren now knows what was wrong with his car.
When asked by AUTOSPORT if his setup choice had led to the car's poor handling, Hamilton said: "It didn't actually.
"I know my car very well, so it's very rare that I get it wrong. And if I do it's only a little bit and I can still manage it.
"But this was the worst it has ever been set up, and I was really shocked that I had done that.
"I hoped it wasn't my fault, but fortunately the guys did a lot of analysis after the race and found our that we had a failure on part of the rear suspension, so that's comforting."
When quizzed on the exact nature of the problem, Hamilton added: "It's not a suspension failure, because I could still drive with it.
"There was just a part that helps the balance and when you set it up it should react in one way but it didn't do that.
"I'm happy that we found something, so it won't be a problem for this weekend."
The Briton added that Fernando Alonso and Sebastian Vettel were right not to rule him out of championship contention following a weekend that left him 42 points adrift in the title race.
"I don't think it's them being polite," he said. "We have a competitive car so we are still in the fight.
"We were quicker than them at Singapore and Monza, so we are still one of the dominant forces in the championship.
"We should have had 35 points from the last two races, but there's still 125 points to go and we've got to keep pushing. You just have to give it your all and wait for the outcome."