Even after a superb summer, Robby Ginepri was not supposed to make it this far.

The 22-year-old American, who won the second title of his career in Indianapolis in July, was going to be a second-round fall guy at the U.S. Open, a minor character in the saga Andy Roddick would write these two weeks in Flushing. Ginepri had beaten Roddick in Indianapolis, but surely he would not do it again when they met inside Arthur Ashe Stadium. He had spent his entire career in Roddick’s shadow, enduring beatings in juniors and during their first six matches as professionals. The one victory was a fluke.

But in stepped Gilles Muller, and now Ginepri’s role – and hopes – could not be more different. Roddick is still looking for his mojo, the once magnificent Muller had a meltdown, and Ginepri has moved into the third round. He claims he is taking things a step at a time, one point at a time, as tennis players are fond of saying, but he must know that the semifinals are well within the realm of possibility.

Ginepri did not just beat Muller yesterday, he pummeled him, 6-1, 6-1, 6-4. After sparkling under the lights of Ashe two nights ago, Muller, the lefty from Luxembourg who stunned Roddick on Monday night, looked rather ordinary in the light of day. In the second set on Louis Armstrong Stadium, he came within a few shots of being shut out. Such a mismatch was this contest that Ginepri, who plays doubles with Muller, expressed surprise at the result.

“Everybody can play at the top of their game or at the bottom,” Ginepri said. “You never know what happens until you step on the court.”

Until this summer, we all could predict what would happen to Ginepri. He might win a round here or there, perhaps even take a set off a quality player. But in the end he would lose more often than not, something he did for his first 150 matches on the tour.

Ginepri said he was disappointed by his performances at the French Open and Wimbledon (both first round losses), but he didn’t hit bottom until he lost in the second round in Newport, R.I., the first week of July. His ranking, once as high as 25 in the world, fell precariously close to 100, the cutoff point for players who want to enter Grand Slam events without qualifying.

“After I lost in a tournament, I didn’t want to practice the next day, I was in a bad mood,” Ginepri said. “If I’m going to do something with tennis in my life, I knew that now’s the time to do it and you can’t wait to be in a good mood. And the days that you’re not, you got to push through them.”

Ginepri redoubled his practice routine and weight training. He began visiting a sports psychologist. Rather than playing like Roddick, banging serves and forehands and trying to hit his way out of trouble, he has learned patience, the virtue of keeping balls in play and picking his spots. Two weeks ago he won a set off Roger Federer.

“I’m a lot smarter upstairs now,” he said. “I don’t make any stupid unforced errors like I used to. I don’t check out in the middle of points.”

The same could not be said for Muller yesterday. The mighty forehand that rattled Roddick had turned to mush. His serve, the cause of 24 aces against Roddick, produced just five yesterday. Unlike Roddick, Ginepri cleaned up on Muller’s second serve, winning 58% of those points. Unlike Roddick, he played a thinking man’s game, hitting more balls to Muller’s forehand, pulling him off the court, and leaving his backhand open for attack.

As the Open heads into its first weekend, Ginepri has perhaps the easiest path to the semifinals. With Roddick gone and two other seeded players – Jiri Novak, who withdrew with an injury, and Mariano Puerta, who lost yesterday – out of contention, Ginepri would not face a player inside the top 10 until the quarterfinals next Wednesday, where he’d likely draw no. 8 Guillermo Coria. Next up is Tommy Haas, a dangerous player seeded no. 29 and just now finding his form after recovering from injuries. On Monday, he might have to contend with Richard Gasquet, the wildly talented but often erratic no. 13 seed, or Ivan Ljubicic, who has tailed off of late after playing exceptional tennis during the first three months of the season.

Three months ago, those men would have been favored against Ginepri, perhaps heavily. Now, they are just opponents, just good players standing between Ginepri and a pile of ranking points, a better standing in the world of tennis.

“It feels good,” he said. “It’s exciting. I’ve been waiting to play like this for a while. I knew I had it inside me, and [I’m] just letting it come out now.”