Marco Simoncelli came into the US MotoGP weekend with three successive race finishers under his belt - his longest points run in a crash-packed season - but hit the deck for the fifth time in ten starts on race day.

Unlike at Assen, where he was able to rejoin, the San Carlo Honda Gresini rider was left to make the long walk back to the pits after his seventh lap accident, which occurred while holding fifth place.

"I am really disappointed. I don't know whether I would have caught Pedrosa [third] if I'd stayed in the race, it's impossible to say, but I could have definitely had a battle with Dovizioso and Spies [for fourth] so it's a real shame," said Simoncelli.

"We had worked so well and managed to improve from session to session but I realised early in the race that the front was giving me more trouble than it had in practice. It closed in turn seven on the first lap, which is a strange place for it to go, and then again two laps later in turn eight.

"All we can do right now is dust ourselves down and head to Brno looking to do our best again."

Simoncelli was one of three riders to crash out, the others being Cal Crutchlow (Tech 3) and Alvaro Bautista (Suzuki).

Team manager Fausto Gresini said Simoncelli's disappointment was clear.

"I can see how gutted he is because he wanted to continue the positive trend of results from the past couple of races but this has been a tougher weekend and he has still been close to the pace of the top guys," said Gresini.

"We knew it would be difficult for him to stay with them today because they had two or three tenths more in terms of race pace but fourth or fifth place was within Marco's grasp. It's a shame but this is racing, so what we do now is put this race behind us and look forward to the next one in good faith."

Team-mate Hiroshi Aoyama finished tenth on his satellite spec RC212V.