New York ? James Blake made Roger Federer work a whole lot harder than he’s used to, and it still wasn’t nearly enough.

The top-seeded Federer dropped a set against No. 5 Blake and faced all kinds of trouble before pulling out a 7-6 (7), 6-0, 6-7 (9), 6-4 victory on Thursday night at the U.S. Open to reach a record-tying 10th consecutive Grand Slam semifinal.

Federer was so masterful at times that even Blake and the partisan crowd in Arthur Ashe Stadium showed their admiration.

Some of Federer’s most impressive offerings drew shouts of “You’re too good!” from Blake, who came into the night 0-4 against Federer, having lost all 10 sets they’d played.

But the highest-ranked American did not go quietly, saving a total of three match points and breaking Federer twice when he served for the match, at 5-3 in the third set and 5-2 in the fourth.

Right until the very end, Blake gave Federer a tough time, holding a break point in the final game and staving off two match points. Blake also saved a match point in the third-set tiebreaker and certainly had other chances: He wasted set points in the opening tiebreaker and three break points at 1-0 in the fourth set.

“It took a while today, but look, it’s tough,” Federer said. “You make mistakes, he plays well, and momentum shifts.”

Martina navratilova reacts after a winner in Thursday's mixed doubles match at the U.S. Open. Navratilova and Bob Bryan advanced to the semifinals.

Federer, the two-time defending champion, advanced to a semifinal Saturday against No. 7 Nikolay Davydenko, who dropped the first two sets in a half-empty stadium, then came back to beat No. 14 Tommy Haas, 4-6, 6-7 (3), 6-3, 6-4, 6-4.

The other men’s semifinal will be No. 9 Andy Roddick against unseeded Mikhail Youzhny, who beat Rafael Nadal in the quarterfinals Wednesday.

Davydenko and Youzhny give Russia two men’s semifinalists at a Grand Slam tournament for only the second time in the Open era, which began in 1968. Marat Safin and Yevgeny Kafelnikov lost in the final four at the 2001 U.S. Open.

The women’s semifinals today feature three women who’ve been ranked No. 1 and won at least one Grand Slam title. No. 1 Amelie Mauresmo plays No. 3 Maria Sharapova, and No. 2 Justine Henin-Hardenne plays No. 19 Jelena Jankovic, who never made it beyond the fourth round of a major until this tournament.

Martina Navratilova extended her remarkable career by at least one more match by teaming with Bob Bryan to reach the mixed doubles semifinals with a 6-3, 6-4 victory over Anna-Lena Groenefeld and Frantisek Cermak.

Roger Federer of Switzerland rests during his match against James Blake of the U.S. on Thursday at the U.S. Open. Federer won the quarterfinal, 7-6 (7), 6-0, 6-7 (9), 6-4.

Navratilova even hopped into the stands after chasing one shot.

“You’re only as old as you feel, and I certainly don’t feel 49,” said Navratilova, who owns 58 Grand Slam titles in singles and doubles and is retiring for a second time after this tournament. “I just wanted to inspire people.”

Navratilova and Nadia Petrova were eliminated in women’s doubles earlier Thursday, losing to defending champions Lisa Raymond and Samantha Stosur, 7-6 (1), 6-3.

Blake, meanwhile, never has been past the quarterfinals at a Slam; he lost at the same stage here last year to Andre Agassi.

Federer, meanwhile, hasn’t lost before the semifinals at a major since the 2004 French Open.

His 10 semifinals in a row matches Ivan Lendl’s run from 1985-88 as the longest in the Open era, and Federer is aiming for his ninth Grand Slam title.

He hadn’t lost a set at this tournament until Thursday, and he sure came close to dropping the opener against Blake. Federer broke at love for a 5-4 edge with a spinning return, but Blake broke right back with the help of a double-fault and two unforced errors.

They went to the tiebreaker, where Blake won five straight points to 6-4. Federer erased the first set point with an ace, and Blake gave away two others with a long forehand, then a return into the net.

Blake’s body language was negative by the end of the lopsided second set, his shoulders slumping, and one fan extolled him: “Put up some fight!”

Blake complied, suddenly playing even with the best player in the world. The highest drama came in the third-set tiebreaker. Federer was a single point from winning at 9-8 after a 30-stroke exchange ended with Blake dumping a backhand into the net. But Blake extended the match with a backhand winner down the line.