NEW YORK - As hilarious after his U.S. Open quarterfinal victory as he was good during it, Novak Djokovic treated an appreciative audience to his spot-on impersonations of Maria Sharapova and Rafael Nadal.

It was a scene most likely never before seen at a Grand Slam tennis tournament - or any sporting event of any significance, for that matter. First, Djokovic did Sharapova, hopping behind the baseline the way she does, bouncing the ball the way she does, pretending to tuck strands of hair behind his ears, and capping it off by doing a perfect rendering of the two-time major champion's serve.

Next, Djokovic did his take on Nadal, sprinting the way he does, even yanking at the back of his shorts the way the three-time French Open champ does.

The act, prompted by USA Network's postmatch reporter, was the most entertaining portion of Thursday's activity in Arthur Ashe Stadium - and showed, without a shadow of a doubt, that Djokovic is poised to become tennis' next star.

He already is a hit on YouTube, where his imitations of fellow pros are posted.

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

“It's funny. He does it very well. That's a gift,” Moya said, referring to Djokovic's renditions. “If he doesn't succeed in tennis, he has a career in that.”

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.

“This is just a matter of concentration. I'm trying to really focus and not irritate anybody. Sorry if I'm a bit annoying,” Djokovic said. “The thing is, I want to stay longer on this court, so that's why I'm bouncing more and more.”

Unlike at the French Open, where he lost to No. 2 Nadal, and at Wimbledon, where he stopped because of an injury while losing to Nadal, Djokovic will finally face a different foe.

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 counted as Djokovic's breakthrough moment.

It also 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 Friday against No. 1 Justine Henin.

After eliminating Serena Williams in her previous match, Henin will try to become only the second woman to beat both sisters at the same Grand Slam tournament.

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

There was an all around more subdued vibe in Arthur Ashe Stadium on Thursday, a sort of hangover effect following up on Wednesday's electric atmosphere for the Federer-Roddick and Venus Williams-Jelena Jankovic matches.

It didn't help that Djokovic and Moya were hardly at their best, combining for only 16 winners and 30 unforced errors in the first set.

Djokovic, though, was just better enough throughout.

In the tiebreaker, he erased Moya's set point, and then converted his second, bouncing the ball 23 times before hitting a 123 mph serve that set up a forehand winner.

Djokovic then broke to start the third set, and that was pretty much that against Moya, a former No. 1 who won the 1998 French Open.

Against Chela, Ferrer kept up his surprising run - and it turns out he hasn't been eating as well as he's been playing.

It was a far shorter and less taxing match than in the previous round, when Ferrer was on court until nearly 2 a.m. while stunning Nadal.

After that rousing victory, the biggest of his career, Ferrer had a hard time finding something for dinner.

So he wound up eating a fast-food burger.

“Yeah, really, at 4:15, my coach and me walk into the McDonald's,” Ferrer said.

He leads the ATP in most major returning categories, and he was up to his usual tricks against Chela, compiling 16 break points.

That count already was up to 12 by the time Chela earned his first break chance on Ferrer's serve.

Chela converted it to take a 2-0 lead in the second set - then promptly got broken right back when he sailed a forehand wide.

“That,” Chela acknowledged, “was my only real chance.”

Before seeing off Nadal, Ferrer escaped a match point against 2002 Wimbledon runner-up David Nalbandian in the third round.

“The last three matches is my best tennis,” Ferrer said. “For me, it's unbelievable.”