First lap mayhem decimates field

The retirements included both McLarens and Toro Rosso's Scott Speed, making his home debut as the first American Formula One driver to race in the US Grand Prix since Eddie Cheever at Phoenix in 1989.

"That's motorsport isn't it? We were just in the wrong place at the wrong time," said the Californian.

"We had a great weekend up to this point and one of these days things are going to go our way and we're going to have a great result."

The pile-up started after the midfield runners bunched into the first corner with Brazilian Felipe Massa leading Michael Schumacher in a Ferrari one-two.

Colombian Juan Pablo Montoya ran into the back of Finnish teammate Kimi Raikkonen -- triggering a chain-reaction that sent Nick Heidfeld barrel-rolling off in his BMW Sauber.

"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," said Montoya.

Australian Mark Webber's Williams, Red Bull's Austrian Christian Klien, Super Aguri's Franck Montagny also retired while Honda's Jenson Button limped back to the pits with low water pressure as the safety car came out.

Button's problem proved terminal as well.

"I don't know what happened. I think Montoya hit my back wheel," said the Briton. "He had enough room on the inside, he had so much room, I don't know if he just understeered or he just hit Kimi up the (backside).

"Then he just pushed me into Heidfeld...it was just amazing I could drive away really, it shows how strong our car is."

Midland's Portuguese Tiago Monteiro made it through the trouble but was taken out at turn one on lap seven in a collision with Super Aguri's Takuma Sato after the safety car came in.

"I was really happy and relieved because I saw two cars rolling, it was a big mess and I saw a gap," said Monteiro.

"I actually made contact with another car but I was able to go good...and then suddenly one of the Aguri drivers tried to win the race in the first lap."

Last year's race saw just six cars start, a Formula One record, after the Michelin-equipped teams withdrew for tyre safety reasons.