After four years, Marat Safin has at last emerged from his own shadow.

Displaying his immense talent and a newfound toughness, the Russian celebrated his 25th birthday by beating the seemingly invincible Roger Federer, 5-7, 6-4, 5-7, 7-6(6), 9-7 in the semifinals of the Australian Open. Safin fought off a match point in the fourth set and survived the mental anguish of losing six match points of his own before ending a four-hour, 35-minute affair.

Numerous times Safin seemed determined to find a way to lose. Serving at 5-3 in the fifth set, he missed two backhands on match points. With Federer facing break point at 4-5, Safin played a flawless series of shots, making Federer scramble at the net. But when he had a short forehand and a lane in front of him, Safin pulled up on his swing and tried to guide the ball past Federer, who closed off the opening with a winning backhand volley. Federer did his part, too, wiping away one match point with a service winner and earning an advantage with a swinging forehand volley.

Under so much pressure, the Safin of years past would have folded. This time he stuck with it, setting up his victory with a backhand down the line that caused the sprinting Federer to fall down. Federer returned the ball, but Safin was left with an easy forehand and an open court.

Out with Federer went a 26-match winning streak and the first outside chance at a single-season Grand Slam in almost 20 years of men’s tennis. Federer won three Grand Slams last year and hadn’t lost to another top-10 player in 15 months. A year ago, he blitzed a depleted Safin in the Australian final, after Safin had won consecutive five-set matches. On Sunday, Safin will have a shot at his second Grand Slam title when he meets the winner of Friday’s semifinal between Andy Roddick and Lleyton Hewitt.

“It was one of the toughest matches I ever had in my life,” Safin said. Talking to reporters at 1 a.m., he said he would celebrate with a glass of champagne, and then spend the next two days limbering up.

The victory was the biggest in Safin’s yearlong return from the brink of irrelevance. At age 20,he played the match of his life, whipping Pete Sampras – winner of his previous eight Grand Slam finals – 6-4, 6-3, 6-3 to win the 2000 U.S. Open. It was a performance so good that at the time it seemed reasonable to suggest that no one could play tennis any better. Safin looked like a tight end yet moved with grace, and he possessed every shot. The future belonged to him.

And then just as suddenly, Safin packed up his incredible gifts and went on vacation. Sure, there were victories here and there, even an appearance at the 2002 Australian Open final, but nothing worth mentioning in the same breath as his one great achievement. His temper too often got the better of him. He smashed rackets, didn’t train, and suffered injuries. When he fell behind, he tanked against inferior players. He talked about quitting tennis altogether.

Thursday evening in Australia, the old Safin awoke from a long sleep. More impressive than his shot making was Safin’s grittiness, his unwillingness to crumble after failing to cash in on numerous chances. He still threw his rackets, and he still shrugged his shoulders, berated himself, and shook his head in despair. Yet he never dropped his head so far that he couldn’t pick it back up again.

“I proved to myself that even though I couldn’t take my chances, there will still be another chance if you keep on going and keep on waiting and keep on just hanging in there,” Safin said. “If you really want it, if you really deserve it, it will come.”

Federer started fast, but wore down as the match progressed. In the fifth set, he asked the trainer to work on his back and elbow. Afterward, he said those injuries hardly affected him, though he was bothered most of the night by a blister on his foot. Federer, as is his habit, was gracious in defeat.

“I thought I gave it all I had,” Federer said. “He was the better player in the end.”

True enough, but on paper, Federer had the look of a winner. He hit 22 aces compared to 16 for Safin, made seven more winners (72 to 65), committed one fewer error (59 to 60), and won more points, 201 to 194. Each player broke serve four times. Though Federer seemed to struggle on his service games more than Safin, he outdid Safin 82% to 74% on first serves and played him even on second serves. He faltered in only one category – double faults, where he had eight to Safin’s one.

So how did Safin do it? Did Peter Lundgren, his coach and Federer’s former mentor, reveal the secret to the game’s most dominant player?

“That’s the question that everybody wants to hear the answer to,” Safin said. “But I’m not going to tell.”

While Andre Agassi avoided Federer’s deadly forehand at all costs, Safin was not afraid to attack it, especially if he could make Federer hit it on the run. Early in the match, Federer had no trouble with the tactic, but by the fourth set, he looked to be off balance, leading to uncharacteristic errors.

Federer also did himself in with poor play at several crucial moments, none more important than the fourth set tiebreak. He took a 4-1 lead with a backhand drop shot that spun off the court. Soon he was ahead 5-2, with two serves coming his way. Last year, Federer won 21 tiebreak sets and lost only five, while Safin compiled a far less impressive record: 26 up and 29 down. The match was in the defending champion’s hands, but he inexplicably went belly up.

With Federer serving for the match at 5-4, Safin pulled out the showstopper. Federer served and volleyed, stretching to make one backhand volley and then another. As the ball neared its second bounce, Safin charged it and flipped a lob over Federer. The Swiss raced back, hit the ball between his legs … and into the net.

From there Safin never trailed, staving off a break point early in the fifth set and capturing a break of his own on a Federer double fault.

“It’s really a pity,” Federer said. “I had my chances, but he didn’t allow me to take them.”

Will the Russian maintain his winning ways? Knowing Safin, there are plenty of down days to come. Let’s hope that on Sunday he’s still on the way up.