Defending U.S. Open champion Novak Djokovic beat 2009 winner Juan Martin del Potro 6-2, 7-6 (3), 6-4 on Thursday to reach the semifinals at a 10th consecutive Grand Slam tournament.
The showcase matchup was compelling throughout, and closer than the scoreline indicated. The thrilling second set lasted 84 minutes — 11 more than Djokovic's entire first-round victory last week.
The second-seeded Djokovic will face fourth-seeded David Ferrer of Spain on Saturday. Ferrer advanced to his fourth career major semifinal by using his high-energy brand of tennis to outlast eighth-seeded Janko Tipsarevic of Serbia 6-3, 6-7 (5), 2-6, 6-3, 7-6 (4) in 4 hours, 31 minutes.
Locked in a taut, thrill-a-minute second set, Djokovic and Del Potro headed to a tiebreaker and promptly produced a 20-stroke masterpiece of a point befitting a pair of past U.S. Open champions.
More than a dozen shots in, Djokovic put up a lob. Del Potro sprinted with his back to the court, got to the ball and lofted a lob the other way. Djokovic slammed an overhead. Del Potro somehow kept the ball in play. Djokovic laced a drop shot. Again, del Potro got there, attempting another lob. It landed long.
A point from a two-set lead, Djokovic threw his head back, roared ''Come on!'' and pumped his arms. Del Potro leaned his elbows atop the net, hunched over and rested his head on his arms.
Close and compelling as their quarterfinal was, it might as well have been over right then and there. Djokovic's down-the-line backhand winner moments later ended the tiebreaker, gave him a commanding lead, and sent him on the way to his win.
''We played some incredible rallies and incredible points,'' Djokovic said. ''It's always entertaining, always so much fun, playing in these night sessions.''
Olympic champion Andy Murray and 2010 Wimbledon runner-up Tomas Berdych — who ousted 17-time major champion Roger Federer — earned their semifinal berths Wednesday.
Under the lights at night in Arthur Ashe Stadium, the showcase matchup of Djokovic's defense, reflex returns and line-catching groundstrokes against the seventh-seeded del Potro's big forehands lasted a few minutes past three hours. But it was tremendously good every step of the way.
These are the only two men who have managed to beat Federer and Rafael Nadal, owner of 11 major trophies, in the course of a single Grand Slam tournament. Djokovic and del Potro each did it while on the way to the championship at Flushing Meadows.
In the three years since del Potro's triumph, though, he hasn't reached another major final. He was sidelined for most of the 2010 season — and missed out on a chance to defend his U.S. Open title — because of a right wrist injury that required surgery. And he's had problems with his left wrist recently, limiting the effectiveness of his two-handed backhand.
Still, he beat Djokovic for the bronze medal at the London Olympics last month and gave the the Serb all he could handle throughout the second set. In what would turn out to be the match's final game, del Potro — who ended Andy Roddick's career by beating him Wednesday — at least got a chance to briefly celebrate on what has become Djokovic's territory, smacking a brilliant backhand winner and hopping on a courtside advertising wall while raising his arms overhead.
''It's amazing for me to share with the crowd this kind of moment,'' del Potro said.
But otherwise, this was Djokovic's night to shine. He is into the U.S. Open semifinals for the sixth year in a row, and the streak of 10 he has at all major tournaments — dating to Wimbledon in 2010 — ties Rod Laver and Ivan Lendl for the second-longest, behind Federer's record of 23.
''He's playing better and better, every day and tournament,'' del Potro said.
Djokovic is bidding to raise his Grand Slam trophy collection to six, and on Thursday he displayed all of the skills that have carried him to the titles. He dulled del Potro's intimidating serves, accumulating 13 break points and converting four. He served well enough to face only three break points himself, saving all but one. And he grabbed control of lengthy baseline rallies, racing and stretching and contorting his body to get to shots del Potro figured would have been winners against just about any other opponent.
Del Potro said Nadal is the only man whose ability to track down tough shots and get them back over the net to extend a point can be compared with Djokovic's.
''It's amazing what they do,'' he said.
What will be remembered most is that marvelous second set, one which del Potro led 5-3, and served for at 5-4 but got broken. One that included a game of more than 15 minutes, when del Potro served while suddenly trailing 6-5 and needed to save three set points. He held, sending it to the tiebreaker. When the set ended, del Potro grabbed a black gym bag and headed to the locker to change his sweat-soaked clothes.
The only remaining question about the outcome arose early in the third set, when Djokovic winced and clutched at his left side after lunging for a backhand. He flexed his back a bit, and stomped his feet, and played well enough to avoid fretting about any sort of comeback.
Earlier, Ferrer needed a mid-match pedicure of sorts, seemed bothered when Tipsarevic got a mid-game medical timeout and, worst of all, was down 4-1 in the fifth set.
In the end, though, the Spaniard was just better, as he usually is when matches go the distance. He has won four consecutive five-setters and is 17-9 overall. When the match ended on Tipsarevic's backhand into the net, Ferrer raised his arms, then knelt near the baseline. The weary foes met at the net for a hug.
''I don't have words,'' said Ferrer, who reached the semifinals at the French Open in June. ''It was a very emotional match.''
