WIMBLEDON, England - A door closes, and another opens. Change is the constant in sport, indeed in life. The familiar merges with the unknown, forcing us to consider the future even as we wistfully think about the past.

Tennis has changed. Wimbledon has changed. Roger Federer exits for a second straight year after a quarterfinal, and we wonder once more whether his time has passed.

Jo-Wilfried Tsonga accomplishes the impossible - or what had been impossible - by losing the first two sets to Federer, then winning.

Has his time arrived?

"I think,'' said Tsonga. "I'm the kind of player who likes these big moments."

In his career, Tsonga, 26, hasn't had many bigger than this, playing Friday in the singles semifinals of the oldest tournament on the globe, the 145th All England Lawn Championships. He faces Novak Djokovic on historic Centre Court, to be followed by the match between defending champion Rafael Nadal and the man carrying the hopes of Britain, the Scot, Andy Murray.

The other three players are where they are supposed to be: the No. 1 seed, Nadal; the No. 2 seed, Djokovic, and the No. 4 seed, Murray. Absent is the No. 3 seed, Mr. Federer, who for the first time in a career now in decline lost a match - to Tsonga - in a Grand Slam in which Federer had won the first two sets.

"I was feeling really strong,'' said Tsonga, "because I never - how you say that? - panic. I was not scared on the big points. I just have to hit the ball, and that's it."

Tsonga is seeded 12th, an outsider but nearly an insider, a fighter in the metaphorical sense, although his facial resemblance to Muhammad Ali and his 6-foot-2, 200-pound size make you believe he could hit an opponent the way he does a tennis ball.

"No,'' Tsonga replied to an all-too-frequent question, "I never met Ali for the moment. But of course I have the possibility to."

If the phrasing isn't quite as smooth as the forehands, it is understandable. He is French, so the English words do not always fit in the proper order.

Jo-Wilfried's father, Didier, is from the Republic of the Congo. He saw the real Ali box Ken Norton in Zaire in 1974, the so-called Rumble in the Jungle. Eventually Didier moved to France to play professional team handball, that rough-and-tumble game that blends lacrosse, basketball and throw-it-don't-kick-it soccer, as well as to study chemistry. He met the woman he would marry, Evelyne, and there was no question their first son was going to be an athlete.

"From my mother I've inherited my coolness and my serenity,'' Jo-Wilfried told the Daily Record, a Scottish newspaper. "From my father I've inherited respect for the rules and people. I also thank him for the physical qualities I inherited."

Meaning size, speed and strength. He looks as if he should be darting for first downs. Instead he's serving aces and chasing down lobs.

His breakout performance came in the 2008 Australian Open, when he made it to the finals, only to be beaten by Djokovic, who always seems to be in his way.

"I think he is more consistent than me," Tsonga said of Djokovic, whose 43-match winning streak ended at Federer's hand at the French Open. "But he hit the ball maybe slower. But I serve really well at this time. We are different character, different personality. We will see."

What we already see in Tsonga is a free spirit who, although intent on success, approaches tennis as a game. He is emotional and personable. After upsetting Federer on Wednesday, Tsonga was making the rounds from one television network to another without a bleat of dismay.

His honesty is disarming.

"I was just perfect,'' he said.

His humility is beguiling.

"Roger is the best,'' Tsonga insisted. "I don't think he's scared of me."

It's not a matter of fear but of respect. When Federer was beaten in the quarters by Tomas Berdych a year ago, Federer unconscionably gave little credit to Berdych, saying, in effect: "I lost it. He didn't win it."

But this time, Federer praised his opponent's tennis, as a six-time champion, as the individual who has a record 18 Grand Slam titles, definitely should.

"He played an amazing match," was Federer's assessment of Tsonga. "He hung in there. I was controlling the match. Next thing you know, he just continued serving great. Then he only needed a couple of breaks to end up bringing it home. He really did a good job."

The perspiration was obvious. The inspiration?

"From France,'' answered Tsonga. "From Congo. From my family. From my house. From everywhere. That's it."

Indeed. That's it. That's Jo-Wilfried Tsonga.