Daniel Ricciardo, HRT, Singapore 2011Daniel Ricciardo expects the Singapore Grand Prix to be the toughest challenge of his Formula 1 career to date because of the race's physical demands.

The Red Bull-backed Australian is heading into only his sixth grand prix. But despite many rating the Singapore race, which is expected to last close to two hours, as the season's most punishing, Ricciardo is confident that he is equal to the challenge.

"I've found this to be the hardest of the six full events that I've done so far," Ricciardo said. "This has been the most difficult physically with the unreal humidity. Everybody talks about the conditions and I expected it to be warm; it's definitely lived up to expectations.

"Street circuits are always challenging, particularly with the Turn 10 chicane where we saw [Kamui] Kobayashi going off. The driving and the physical side is definitely the most difficult so far this year. It's going to be a long race and very hot, but I think we are well set for it."

The 22-year-old will start 23rd on the grid and admitted that he was disappointed to be outqualified by the Virgins after lapping only two tenths off Jerome D'Ambrosio. But he is hopeful that, with a good start, both d'Ambrosio and Timo Glock might be beatable in the race.

"I think it is possible to beat them," said Ricciardo. "It's hard to say where we are at from Friday's longer runs, but normally in the races, if we can get ahead of them at the start we seem to be able to match their pace.

"If they are a fair chunk quicker in qualifying, we usually close that gap for the race. So considering we're not too far off in qualifying I expect us to be more or less there with their race pace. We'll see how the start goes and play it from there."