NEW YORK -- Racket bag slung over his shoulder, Andre Agassi briskly walked out of the locker room and through the halls of Arthur Ashe Stadium to the VIP parking lot.

He piled into a silver car and drove off at 3 p.m. on Saturday, exactly 24 hours before the start of the U.S. Open men's final. Agassi won't be back for that, and he won't be No. 1 any longer, either, after losing his semifinal and the top ranking to Juan Carlos Ferrero of Spain 6-4, 6-3, 3-6, 6-4.

While Agassi was making his exit, a younger American, Andy Roddick, was in the process of digging a two-set hole in the second semifinal. To the delight of the crowd and, no doubt, CBS executives, Roddick came all the way back, pounding a career-high 38 aces to beat No. 13 David Nalbandian of Argentina 6-7 (4), 3-6, 7-6 (7), 6-1, 6-3.

"I'm pumped. I came here so many times when I was younger, and I can't believe I'm actually in a U.S. Open final," said Roddick, the 2000 junior Open champion.

"It would be great to go one step further."

With Kim Clijsters and Justine Henin-Hardenne meeting in an all-Belgian women's championship match late Saturday night, a loss by Roddick would have meant no Americans in either singles final at a U.S. Open for the first time since 1988.

But Roddick showed real grit, erasing a match point in the third set en route to his season-leading 18th straight victory. He's 36-2 since teaming with coach Brad Gilbert, Agassi's former mentor, after a first-round exit at the French Open.

"It's maturity. By playing, you learn. I feel confident right now, so I didn't feel there was a need to panic," Roddick said, referring to his two-set deficit. "To come through that gave me new life. I was almost down and out anyway. I just decided to go for it."

The fans did what they could to spur on both Agassi and Roddick, occasionally cheering faults by their opponents.

Now, after losing in the semifinals at the Australian Open and Wimbledon, No. 4 Roddick will make his debut in a Grand Slam final. Ferrero, who came into this tournament ranked third, won the French Open for his first major title.

"America is pretty big. If you don't play pretty good tennis here, the people don't know you," Ferrero said, smiling.

Remarkably, he outslugged Agassi from the baseline, all the while zipping from corner to corner with the speed that earned the nickname "Mosquito."

"To be at No. 1, it's a special day for me," Ferrero said. "I am playing good. I have a lot of confidence. I can do every shot."

He sure can, none more spectacular than one through his legs with his back to the net in the third set. Agassi volleyed that back, and Ferrero switched directions and sprinted up for a crosscourt forehand passing winner.

"He was just taking care of his business better than I was," Agassi said. "By the time I was getting into the match, I was already two sets down. So that's difficult."

Agassi is 33, the Open era's oldest top-seeded man, and as impressive as his conditioning is, he fared much poorer than the 23-year-old Ferrero did in the 80-degree afternoon. Rain during the week forced a schedule crunch that eliminated the normal day off between the quarterfinals and semifinals.

Agassi was sluggish at times, simply waving his racket at one forehand return winner by Ferrero instead of stepping over to attempt to reach it.

"I wasn't quite using my legs as well as I normally do," Agassi said. "But this hasn't been easy for any of the players. He dealt with it better than I did today."

Some players thought it wasn't fair that Agassi and Roddick got more time off during the week of bad weather, because their fourth-round matches finished before the other six did.

"It's difficult to play three days in a row," Nalbandian said.

Ferrero will have his fourth match in four days Sunday, the first time anyone has been asked to do that at a Grand Slam tournament in the 35-year Open era.

"He played great against Andre today," Roddick said.

Nalbandian also had shorter rest: Roddick was off Thursday, when the 2002 Wimbledon finalist was playing his fourth-round match. And Nalbandian complained about wrist and stomach injuries Saturday.

"I thought I had a little bit left in the tank, a little bit more than he did," Roddick said. "To his disadvantage, he had to play a couple more matches than I did in the last few days."

Roddick lost the first set despite compiling 14 aces, and after sending a return long to lose the second set, he tossed aside his racket as he plopped down in his courtside chair. About the most fight Roddick displayed early came while he was sitting during the initial changeover of the third set, getting a callus on his right foot sprayed and wrapped. Upset at the length of the delay, Nalbandian -- who had his left wrist heavily taped earlier -- went out on court to wait. That prompted Roddick to snap: "Don't worry. I'm playing."

Later in that set, Roddick yelled at chair umpire Andreas Egli for not overruling a call on a double-fault. Roddick saved the true tirade for the next changeover.

"The calls have been bad all day. Terrible. I have not said one word all day," Roddick said, his voice rising. "Step up!"

It was a sign of the old Roddick, the pre-Gilbert Roddick, the one that second-round opponent Ivan Ljubicic complained about.

"Maybe I was just trying to vent frustration," Roddick said later.

The outburst appeared to fire him up.

Nalbandian's match point came at 6-5 in the third-set tiebreaker, but Roddick erased that with a 138 mph service winner. Roddick followed with a 136 mph ace for a 7-6 edge and his second set point, which he wasted with a forehand into the net.

But Nalbandian netted a backhand on a rally during which a fan called "Out!" -- the Argentine complained to Egli about the distraction -- and Roddick ended the tiebreaker with a forehand volley winner.

Suddenly on cruise control, Roddick broke in the first game of the fourth set, which Nalbandian pretty much conceded.

Roddick then broke to 5-3 in the last set. He hit an inside-out forehand winner to earn two break points, and converted the first when Nalbandian's backhand flew wide. Nalbandian disagreed with the call, pointing at the spot where it landed and arguing with Egli to no avail.

"Every time it was close," Nalbandian said, "everything was for" Roddick.

Roddick observed the scene while perched on a courtside sign, then served out the match at love, with one last ace to get to 40-0, where Nalbandian hit a forehand wide.

In the first semifinal, Ferrero refused to be pushed around the court like a marionette whose strings are pulled by Agassi, breaking in the very first game.

At this point in his career, every loss at a major prompts questions about Agassi's retirement. They're more poignant these days now that rival Pete Sampras quit.

"I just have to go back to work," Agassi said. "Something would have to change drastically for me not to be back."