Andy Roddick remains upbeat after pushing Rafael Nadal in a close three set clash on Monday night.

Roddick produced one of his best performances of the indoor season, thumping down 140mph serves on a regular basis and pushing the Spaniard onto the back foot with his aggressive net rushing tactics. For a set and a half it was all Roddick and the American looked set for a shock victory at a set and a break up.

However Roddick could not convert his chances in the second set tiebreak and Nadal hit back, ultimately making the American look a little one-dimensional at times in the final set.

However Roddick knows he still has a good chance of beating Novak Djokovic and Tomas Berdych to qualify for the semi-finals and he refused to be downhearted afterwards, praising the atmosphere created by a packed stadium.

"I thought it was great," he said. "I think we're glad we put a really good product out there tonight. Up until now I don't feel like two players have played well at the same time during a match. It was fun playing tonight.

"I came out of the gates aggressively and I think it caught him by surprise. He definitely wasn't settled comfortably. He was missing more balls than normal.

"I think the difference was he found his range on his forehand in the second and third sets. It hinged on the breaker. I thought I played well tonight."