It was a pitiful sight when Andre Agassi last bowed out of a Grand Slam event, limping off the red clay of Roland Garros after a first-round loss to a French Open qualifier. His chronic sciatica had flared up, shooting debilitating pain from his hip to toes. So Agassi flew home, withdrew from Wimbledon and weighed his options: Retire from tennis at age 35 or sign on for another round of cortisone injections and even more work in the gym.

Recalled longtime trainer Gil Reyes, "I told him, 'You'd better step up, or you're going to get swept away.' "

Three months later, Agassi is one of four men still standing at the U.S. Open and by far the people's choice for claiming what would be his third U.S. Open title and ninth major championship.

On Saturday, he'll face fellow American Robby Ginepri -- whose run to the semifinals has been even more surprising than Agassi's -- for the right to advance to Sunday's final. Saturday's other men's semifinal is a reprise of last year's final, with top-ranked and defending champion Roger Federer taking on third-seeded Lleyton Hewitt of Australia.

It's tough to name an athlete who has aged as gracefully as Agassi. And his exploits here, competing in his 20th consecutive U.S. Open, have only further endeared him to sports fans.

As one of five men to have won all four titles that compose a Grand Slam (the Australian Open, French Open, Wimbledon and the U.S. Open), Agassi would surely have commanded a wild-card entry to the 2005 U.S. Open had his ranking plummeted to the point that he would have been excluded otherwise. Jimmy Connors took advantage of such an honorific on the cusp of his 39th birthday and parlayed fading athletic skills and outrageous on-court antics into a romp to the semifinals of the 1991 U.S. Open.

But Agassi needed no special treatment. Based on his ranking he commanded, the seventh seed and has met every challenge hurled his way -- including a five-set quarterfinal against fellow American James Blake, which he won in a tiebreaker after trailing, two sets to none.

On paper, Agassi should roll past the 22-year-old Ginepri, who has never taken a set from the veteran. But the outcome will likely turn on how well Agassi rebounds from his 2-hour 51-minute quarterfinal, which ended after 1 a.m. Thursday.

Ginepri has reason to be sapped as well, having played three consecutive five-set matches.

Federer is a heavy favorite in the other semifinal, having won his last eight matches against Hewitt. Much like Andy Roddick, Hewitt has never varied his tactics against the peerless Swiss. Asked if Hewitt might be better served by changing his approach, Federer smiled and said: "He could, you know. But then again he could even run into the knife more brutally."

American Robby Ginepri celebrates his win over Guillermo Coria, Ginepri's third straight five-set win. He'll face Andre Agassi in the semifinals today.