Novak Djokovic prevented an eighth Grand Slam championship match between Rafael Nadal and Roger Federer - and the first at the US Open - by saving two match points and coming back to stun Federer 5-7, 6-1, 5-7, 6-2, 7-5 in Saturday's semi-finals.

"One of those matches," Djokovic said, "you'll always remember in your career."

It means that the third-seeded Djokovic will be standing between No 1 Nadal and a career Grand Slam in the final on Sunday.

Nadal owns eight major titles but had never been past the semifinals at the US Open before beating No 12 Mikhail Youzhny 6-2, 6-3, 6-4 earlier on Saturday.

Federer had reached six consecutive US Open finals, winning five trophies from 2004-08, but he repeatedly let leads slip away this time.

Federer took the first set against Djokovic, then the third. And even after Djokovic forced a fifth set, Federer twice was a single point from winning.

With the crowd in Arthur Ashe Stadium trying to will Federer to victory - probably because of the tantalising prospect of a final between him and Nadal - the owner of a record 16 Grand Slam titles couldn't seize his chances.

"They all pretty much feel the same: You feel so empty at the end, I guess, because you tried everything," said Federer, who hadn't dropped a set all tournament before Saturday, but was hurt by 66 unforced errors, 28 more than Djokovic.

"You feel like you left something out there if you lose a match having had match point," Federer added. "It wasn't a final, so I'm not as disappointed if it would have been a final."

This setback comes after losses in the quarterfinals of both the French Open and Wimbledon, and Federer closes the 2010 Grand Slam season having played in one major final - the first year since 2003 that he hasn't reached at least two.

HISTORY BECKONS

Nadal, meanwhile, will be bidding Sunday to become the first man since Rod Laver in 1969 to win the French Open, Wimbledon and the US Open in the same season.

The 24-year-old Spaniard also can become the seventh man in tennis history to own at least one championship from each Grand Slam tournament.

"I won't watch," Federer said, "but I hope he wins."

Federer's three-hour, 44-minute loss to Djokovic was far more entertaining than the day's first semifinal.

Nadal dominated with his serve again, holding 13 of 14 times Saturday, making him 89 of 91 for the tournament.

"After a lot of work," said Nadal, who hasn't dropped a set these two weeks, "I am here in the final."

He lost in the semifinals in New York each of the past two years. In 2008, he lost to Andy Murray, and now says he was wiped out mentally after a long, if successful, summer that included a gold medal at the Beijing Olympics. In 2009, he lost to eventual champion Juan Martin del Potro, while dealing with achy knees and a torn abdominal muscle.

"Well, it's another step, I think, in my career, so for sure it's a very important victory for me," Nadal said. "To be in the final of the last Grand Slam of the year is something new, because I always arrived here with problems."

Not this year. He took three weeks off after Wimbledon - skipping Spain's Davis Cup quarterfinal - to rest and get treatment on the knees that bothered him so much of last season and the beginning of this season.

"Tough to say who is better than Rafa," Youzhny said. "I mean, he's No 1 and he played really good tennis."

On a day when the wind that has plagued the tournament finally eased up, Djokovic managed to be better than Federer - barely .