New York ? Novak Djokovic was as hilarious after the match as he was good during it, treating fans to his spot-on impersonations of Maria Sharapova and Rafael Nadal.

The act, prompted by USA Network’s postmatch reporter, was the most entertaining portion of Thursday’s activity in Arthur Ashe Stadium.

The No. 3-seeded Djokovic’s game is quite impressive, too, as he showed by reaching a third consecutive Grand Slam semifinal with a 6-4, 7-6 (7), 6-1 over No. 17 Carlos Moya.

Even Djokovic’s pre-serve routine requires attention. When he faced a set point in the tiebreaker, for example, he kept dribbling the ball, 28 times in all.

Eventually, he tossed the ball overhead – and hit a fault. Before his second serve, Djokovic cut his total to 13 bounces, hit a 113 mph offering, and won the point.

In Saturday’s semifinals, he’ll meet No. 15 David Ferrer – who just happens to be the man who ran Nadal ragged in the Open’s fourth round. Ferrer reached his first major semifinal by beating No. 20 Juan Ignacio Chela, 6-2, 6-3, 7-5, Thursday.

Top-ranked Roger Federer is in his record 14th Grand Slam semifinal in a row and plays No. 4 Nikolay Davydenko on Saturday. Federer is 9-0 against Davydenko and hasn’t fared too poorly against the semifinalists on the other side of the draw – he’s 7-0 against Ferrer, 4-1 against Djokovic.

Djokovic’s one victory over Federer came in their most recent meeting, in the final of a hard-court tournament in Montreal last month. It was at that event that Djokovic became the first man since 1994 to defeat men ranked Nos. 1-3 at the same tournament.

That gave him four titles in 2007, and his 57 match wins through Thursday rank second only to Nadal.

Federer took Thursday off, skipping practice and resting, a day after improving to 14-1 against 2003 U.S. Open champion Andy Roddick by beating him in straight sets.

Venus Williams, though, was out on the practice courts in the late afternoon, preparing for her semifinal today against No. 1 Justine Henin.

The other women’s semifinal is 2004 U.S. Open champion Svetlana Kuznetsova against No. 6 Anna Chakvetadze.