Veteran Carlos Moya [Images] admitted he unravelled after dropping a second-set tiebreaker to Novak Djokovic during their quarter-final match at the US Open on Thursday.

- Images from the match

"I was beat down mentally," Moya said following the 6-4, 7-6, 6-1 defeat to the third-seeded Serb. "Having the chance to be set all would have been much different I guess.

"Being two sets down, he is not as tight maybe as he was and he played much better. And I played a bit worse."

The 31-year-old Moya was perhaps understating the shift of power in the final set. After narrowly losing the tiebreaker 9-7, he was immediately broken to open the third set.

He was broken again in the fifth game and then in the seventh and final game of the match. On match point, the 1998 French Open champion double faulted.

Moya had nine errors in the final set while the third-seeded Djokovic made just one.

The Spaniard had nothing but praise for the 20-year-old Djokovic, who joined Roger Federer [Images] as the only player in 2007 to reach the semi-final of three or more Grand Slams.

"He's been playing very solid almost every week," said Moya, who reached the semis at Flushing Meadows the same year as his Roland Garros triumph.

"Playing three semi-finals in the same year in grand slams is not easy. Still he has a chance to get even further here.

"He can still improve, but he has a lot of potential to be number one in the world."

Djokovic, who was 11 when Moya won the French Open, will shoot for his first grand slam final when he plays 15th seed David Ferrer of Spain in the semi-finals on Saturday.

Moya said Djokovic can already be compared to the world's top- ranked players, Federer and Rafael Nadal [Images].

"I think if there's one player who can be compared to Rafa and Roger it's him," he said.

• Complete tennis coverage
• All you want to know about Sania Mirza