Ducati team manager Vittoriano Guareschi says squad must improve after Indy debacle

The team's best finish in the USA was a 10th place for Valentino Rossi, who dropped to the back of the field after his bike jumped out of gear and into neutral, leaving him without drive momentarily during the race's early stages.

Nicky Hayden, meanwhile, was the only rider in the field to use the softer of the two Bridgestone front tyres on offer, and after running strongly early on, the American was eventually forced to pit for fresh rubber before resuming in 14th and last.

"Today was very challenging for our team and riders, and despite their typical great efforts, we struggled to bring home a few points," Guareschi said.

"After the positive performance at Brno, we expected to find a good rhythm here at Indianapolis as well. We didn't manage it. We know that we have to improve, and no-one at Ducati or in the team is holding back as we work toward that goal."

Rossi said that he had been left low on confidence following a crash early in qualifying, and that his gearbox problem, which struck on a number of occasions, had not helped matters.

"A number of things happened this weekend that contributed to making this a particularly difficult race: the crash yesterday in qualifying, which robbed some confidence and was part of the reason we had to start so far back on the grid, and today there was a problem with the gearbox," the seven-time world champion said.

"The bike stuck in neutral six or seven times, and the first two caused me to go straight and lose time. I found myself in last place, but I decided to do what I could to at least get some points.

"In this morning's warm-up, we had made a small change that let us improve the pace a little, but the race was really difficult. We know that we have to work hard. Ducati is doing that, and my team and I are as well, because we must try to not let up and to get the bike ready while we wait for technical updates."