Andy Roddick might want to think over those retirement plans. The American star won again on Sunday, beating Italian Fabio Fognini 7-5, 7-6 (1), 4-6, 6-4, to advance to the fourth round, where he will play Juan Martin del Potro.

Roddick had a much tougher time against his longtime friend Fognini than he did in his first two matches, struggling with his serve and the Italian's feisty backhand shots. Roddick has advanced further at this tournament than he has at any Grand Slam this year and has won two straight matches since announcing his retirement last week.

In the first set Roddick played aggressively, frequently moving close to the net, working to counter the 59th-ranked Fognini, especially while he was serving.

In the tiebreaker in the second set Fognini had an early lead 1-0 before Roddick took over, winning the next six points, two on aces that were both clocked at over 125 mph. The Italian finally came through in third, taking the set after breaking Roddick's serve in the final game.

Roddick challenged Fognini with shots at the net and forced a break point to go up up 4-3 in fourth set before closing out the match.

Although Roddick is known for his overpowering serve, he only had 10 aces while Fognini finished with 15. Throughout the match Roddick was very animated, clapping and cheering after points and feeding off the frenzied crowd, who was fully supportive of him.

In his Open career, Roddick has advanced to the fourth round eight previous times and has an 8-0 record in those matches.

The fourth round challenge could very well end up being Roddick's last match of his career. His next opponent will be his toughest yet, No. 7 seed and 2009 U.S. Open champion del Potro, who seems to be fully healthy after getting wrist surgery in 2010.

Del Potro beat fellow Argentinian player Lenardo Mayer 6-3, 7-5, 7-6 to advance to the Round of 16. He is also the only player not named Rafael Nadal, Roger Federer or Novak Djokovic to win a major tournament in the past three years.

"I'm going to have to serve well, kind of try to rush him a little bit," Roddick said about del Potro according to ESPN.com news services. "When he gets into a groove and has time, he'll put a hurt on the ball."

Although the odds won't be in Roddick's favor Tuesday night, he will have the support of the crowd, which could help spur what would be the biggest upset of the tournament so far.

Roddick is the only American left in play after Mardy Fish had to pull out of his match against Federer due to medical issues. It is fitting for Roddick considering he has been the most prominent and well-known player from the United States for a decade.

If he could pull out another win he would advance to the quarterfinals of a Grand Slam for the first time since last year's U.S. Open. He lost that match to Rafael Nadal in straight sets.