Andy Roddick was being outplayed, outhustled and even outserved by Guillermo Coria.
Then, suddenly, Roddick summoned up all the skills and grit that made him No. 1.
Down a break in the final set and reeling a bit, Roddick went on a 10-point run to grab the upper hand and pull away for a 6-3, 6-7 (4), 6-3 victory Friday night that put him in the Tennis Masters Cup semifinals.
Roddick went 2-1 in round-robin action and advanced to a semifinal against Wimbledon champion Roger Federer (3-0). Coria (1-2) was eliminated.
The other semifinal Saturday will pit No. 5 Andre Agassi against No. 6 Rainer Schuettler, the man he beat in the Australian Open final. Already assured of advancing, Schuettler lost his last round-robin match 7-5, 6-4 Friday to Carlos Moya.
The fourth-ranked Coria played nearly flawless tennis in the second set and the early part of the third, which he led 3-1. But Roddick won the final five games of the match with some spectacular play -- and with some help from his Argentine opponent.
Coria was up 3-2, 40-love when he missed five consecutive forehands to get broken. Roddick won the next five points, too, including holding at love for a 4-3 edge with the help of a 136 mph service winner.
His serve working much better than it did in the middle portion of the match, Roddick cruised at the end, closing the match with back-to-back aces.
Coria had won the prematch coin toss and chose to let Roddick serve first, as if to say, "Bring it on!"
Coria did return very well for stretches, and Roddick's serve wasn't its best: Among other problems, he double-faulted to hand over the second-set tiebreaker. During the changeover, Roddick chopped his racket into his bag a half-dozen times.
That tiebreaker featured the point of the tournament, a lengthy exchange that finished this way: Coria hit a great reflex lob; Roddick chased it down and, with his back to the net, smacked a shot through his legs; Coria lofted another lob; Roddick pounded an overhead; Coria got to it and delivered a passing shot that Roddick volleyed into the net.
Roddick finished with 12 aces and a total of 38 winners -- 13 more than Coria -- in a riveting match. Roddick was even moved to applaud a couple of Coria's better efforts.
It was a matchup of contrasting styles: Roddick's power against Coria's quickness and touch. Yet both displayed plenty of the other's chief traits.
Roddick showed deftness at the net, repeatedly winning points with feathery drop volleys, and often came out on top of lengthy baseline rallies by expertly changing pace.
Coria, for his part, had just as many forehand winners as Roddick, nine, and was very effective with his serve, holding at love three times in the middle set and saving one break point with an ace.
Now Roddick will take on Federer, who owns a 4-1 career edge, including a straight-set victory in the Wimbledon semifinals this year. The American did win their most recent match, though, at the Canada Masters in August.
Federer is tied with Roddick for the tour lead with six tournament victories in 2003, and the Swiss star's 76 match wins are the most this season.
Federer overwhelmed French Open champion Juan Carlos Ferrero 6-3, 6-1 Friday to give himself a chance of finishing the season ranked No. 2.
"I'm just happy the season is ending nicely," said Federer, who also beat Agassi and David Nalbandian this week. "I was in a tough group, so to come through so easily -- the last two matches especially -- is surprising."