US GRAND PRIX RESULT 1 M Schumacher (Ferrari) 2 F Massa (Ferrari) 3 G Fisichella (Renault) 4 J Trulli (Toyota) 5 F Alonso (Renault) 6 R Barrichello (Honda) 7 D Coulthard (Red Bull) 8 V Liuzzi (Toro Rosso)

Montoya appeared to trigger the crash by running into the back of McLaren team-mate Kimi Raikkonen.

But Dennis said: "There was a chain reaction. It was one of those things.

"The whole thing started to sequence with Juan Pablo running into the back of Kimi and Jenson Button bumping into Kimi pretty simultaneously."

It had appeared from television footage that Montoya knocked into the rear of Raikkonen's car, pushing the Finn into Button, whose Honda then flicked Nick Heidfeld's BMW Sauber into a series of barrel rolls.

A lot of cars were squeezed - I don't think anyone should be too criticised Ron Dennis McLaren boss

But Dennis said McLaren had carefully analysed the data from their cars' on-board computers and several camera angles and come to the conclusion that Montoya was not wholly to blame.

"There was a chain reaction," he said. "Kimi got a little squeezed going into the first corner and braked a little early, but in the circumstances he braked to avoid running into someone.

"Juan Pablo was keeping an eye to the right because Button was starting to close on him and bump him.

"A lot of cars were squeezed. I don't think anyone should be too criticised."

I had a very good start and had already made up three positions - then, all of a sudden, I was airborne Nick Heidfeld

Montoya said: "I was following Kimi when he braked really hard and I hit him in the back.

"There were just cars turning left, right and centre. I was being squeezed by one of the Hondas and regrettably I hit Kimi."

Raikkonen added: "Things got messy at the second corner and Juan Pablo hit me from behind and that was the end of the race.

"There is no point in blaming anyone as these sort of things happen in racing and especially when you are not at the front."

But Button did blame Montoya, saying: "I was approaching Turn Two and we were already three abreast when Montoya decided to get past all three of us at the same time.

"He had a lot of room to go up the inside so I don't really know why he hit my back wheel, but that pushed me into Heidfeld who hit my right rear which launched his car into the air.

"I saw him roll and it was all just a big mess really."

Heidfeld was also unable to point the finger after becoming disorientated following his multiple barrel-roll.

"I escaped unhurt from the accident," said the German. "I don't know exactly what happened. I had a very good start and had already made up three positions.

"Then, all of a sudden, I was airborne."