That is the view of Williams technical director Patrick Head, who said the Colombian would have caught and passed Michael Schumacher's Ferrari.

Head claimed Schumacher would not have been able to defend himself from Montoya's attack in the closing laps because of problems with his car.

Williams technical director Patrick Head said that Montoya would have triumphed without his problems.

"Juan had that race well won," Head said.

"I think Michael was very short on fuel, which is why he was going quite slowly towards the end.

"And there were some problems with blistering tyres [on the Ferrari] so I think Juan would have been in very good shape.

He was later quoted on the team's press release saying: "I was catching Michael quickly. Suddenly I felt a loss of power and that was it. We did everything right but today was not for us."

The Colombian had been closing in rapidly on Schumacher after a tense, tactical battle when the BMW engine in his Williams failed.

It is the second race in a row that Montoya's engine has failed.

And it left Montoya an almost certainly unrecoverable 43 points behind Schumacher in the world championship.

That margin means that with nine races to go, Montoya would have to win four times with Schumacher failing to finish in each race and the Williams man would still trail by three points.

It was also the second time in the season and a half that Montoya has raced for Williams that he has retired from a potentially winning position because of an engine problem.

He lost what would have been his first Grand Prix victory in last year's German event when his engine blew up.

Schumacher did not respond directly to Head's claims, but he did say that he was not worried when his team-mate Rubens Barrichello and David Coulthard in second and third places also began closing on him.

"I was in charge. Whether I win by 20, 10 or one second is immaterial to me."