HOUSTON -- A champagne celebration following a defeat?

	Andre Agassi defeated David Nalbandian 7-6 (10), 3-6, 6-4 to earn a semifinal berth on Thursday.

Welcome to Andy Roddick's world.

About 12 hours after being guaranteed the year-end No. 1 ranking, Roddick went out and lost to Rainer Schuettler 4-6, 7-6 (4), 7-6 (3) Thursday in round-robin action at the Tennis Masters Cup.

Then Roddick's postmatch news conference was interrupted by a bubbly bath courtesy of friend and fellow pro Mardy Fish.

"It's a very sweet day for me. I'm going to try to forget the fact that I didn't play well," Roddick said. "This was a culmination of the whole year. And I wasn't going to spoil that by having a bad attitude just because I didn't play well on one day."

To reach the semifinals, he'll have to win Friday's match against No. 4 Guillermo Coria, who beat No. 7 Carlos Moya 6-2, 6-3.

Andre Agassi, meanwhile, qualified for the final four by outlasting No. 8 David Nalbandian 7-6 (10), 3-6, 6-4 Thursday night. Nalbandian, a point from winning the first set four times, got into an extended argument with chair umpire Enric Molina in the tiebreaker over two line calls and also spoke with tournament supervisor Mark Darby.

Later, the Argentine complained about the officiating ("They can do a better job," he said) and about tournament chairman Jim McIngvale rooting for Agassi in the stands ("It's a lack of respect toward the players").

"I've been on both ends of that before. So I certainly understood the emotions of being frustrated with some calls," said Agassi, whose semifinal against Schuettler will be a rematch of the Australian Open final.

That tiebreaker provided great tennis and theater, with the first of Agassi's four set points arriving at 6-5 when Molina overruled a line judge's out call on the American's backhand. Nalbandian saved that, then eliminated Agassi's next two set points with aces (one on a second serve at 9-8). But at 10-10, Nalbandian put a running forehand into the net, then double-faulted to cede the set.

After Nalbandian eased through the second set with a 15-2 edge in winners, the third set provided more drama. Agassi broke en route to a 4-1 lead, then was broken while serving for the match at 5-3. He broke right back to end it, though. Nalbandian put two straight backhands into the net, then double-faulted to match point. And Agassi closed the match with a forehand volley, making him 21-for-30 on trips to the net.

It was a match filled with extended rallies and spectacular shots by both men -- and another long day's work for Agassi (2-1), who has played three three-set matches. "It feels great to get in a number of tough matches," Agassi said, "because that's what I was really looking for here, to settle into my game and at least feel like I'm competitive out there."

His victory over No. 2 Juan Carlos Ferrero on Wednesday night dropped the Spaniard to 0-2, preventing him from advancing to the semifinals. And that assured Roddick of becoming the 13th man to close a season atop the ATP Tour computer rankings.

"It was kind of unusual that it happened on a Wednesday," said Roddick's coach, Brad Gilbert. "And it was like, 'OK, Andy, you have to go back to business on Thursday.' I think that if Ferrero would have still been in it, maybe he would have been a little more intense today because there would have been more of a sense of urgency."

Roddick's strength, his serve, let him down late, with six of his eight double-faults in the third set, including one to set up match point. He then sailed a backhand long to end it with his 49th unforced error.

That made Roddick's record in the round-robin portion 1-1. Schuettler is 2-0 and into the semifinals.

The tour honored Roddick in an on-court ceremony after he faced Schuettler, presenting him with a crystal trophy marking his ascension.

"It's a pretty big accomplishment for me, something I never thought would happen or was possible," said Roddick, who beat Ferrero in the U.S. Open final. "To kind of just storm through this summer and take it in the latter part of the year -- maybe I snuck up on some people. "I'm ecstatic about it."

A few minutes later, Roddick was soaking wet. Fish, who lived with Roddick's family in Boca Raton, Fla., for a year when they were in high school, ran into the news conference and sprayed two bottles of champagne on his pal's head.

Roddick could have sipped some of the alcohol legally -- but just barely. He turned 21 in August during the U.S. Open; only Lleyton Hewitt, at 20 in 2000, was younger when he reigned at No. 1.

And as recently as late May, Roddick didn't think this honor would come so quickly.

That's when he was surprised in the first round of the French Open by journeyman Sargis Sargsian. Within days, Roddick hired Gilbert, Agassi's former coach. Thanks in part to Gilbert's calming influence and scouting, Roddick went on a tear, winning five titles and nearly 90 percent of his matches.

"For all this to happen, it's just been a whirlwind. It's just been amazing for me," Roddick said. "I don't even know what to say about it. I mean, it's just been an amazing ride over the last couple of months."