US Open: Ex-champs Roddick, Del Potro on collision course

Retirement-bound Andy Roddick and Juan Martin Del Potro booked a fourth-round showdown of former champions at the US Open with the American facing the emotional tension of his next loss being his last.

Roddick, the 2003 US Open winner, advanced with a 7-5, 7-6 (7/1), 4-6, 6-4 victory over Italy's 59th-ranked Fabio Fognini while Argentine seventh seed Del Potro, the 2009 winner, ousted countryman Leonardo Mayer 6-3, 7-5, 7-6 (11/9).

Three days and two matches after US 20th seed Roddick said he would bid farewell to tennis after the Flushing Meadows fortnight, the American produced an electric atmosphere Sunday at Arthur Ashe Stadium before his victory.

"The outpouring of support has been humbling. I appreciate all the support. I really do," Roddick told the crowd. "You guys have made it so special. I'm just enjoying it. I love this place. I love all of you and I'm having a blast."

Roddick, who turned 30 last Thursday, has fought to keep his emotions under control as he contemplates the end of his career while trying to play his best on the court where he won his only Grand Slam crown.

"I'm trying to keep my emotions together all the time while trying to appreciate this tournament," Roddick said. "I know each time I go warm up it might be my last time."

Roddick said not even a championship would change his mind about retirement.

"That would be a hell of an ending, though," Roddick said. "I would take that."

Del Potro, however, wants to pull the plug on Roddick's dream run and claim his second title on the New York hardcourts.

The South American's 2009 title is the only Grand Slam crown in the past 30 not won by World No. 1 Roger Federer, defending champion Novak Djokovic or injured Spanish star Rafael Nadal.

"I know it's special, this day for him, but I'm doing my job," he said. "I'll try to be focused on my match, doing my things, making my shots. The match is going to be very tough but if I play at a high level it will be tough for both players."

Del Potro owns a 3-1 career record against Roddick, all matches coming on hardcourts, with triumphs at the 2008 Los Angeles final, the 2009 Washington final and a 2009 Montreal semi-final.

But Roddick won their most recent meeting last year at a Memphis semi-final.

Del Potro knows that while he receives affection from the crowd, notably from his loyal Argentine backers, that Roddick will be the crowd favorite when they meet on Tuesday.

"Big atmosphere," Del Potro said. "The crowd loves Andy and has respect for me. It will be a fanstastic show to the players and to the fans also. I like to play in these kind of matches."

Roddick feels the same and has never had his career riding on any match to the extent he will against Del Potro.

"It doesn't really matter how much energy I have. You still keep going," Roddick said. "I'm going to give it all I have here."

Roddick admitted that his right shoulder is sore but rejected the idea of an MRI to fully learn the extent of the injury given his impending exit.

"It's not great," he said. "I've got max a week of tennis left. It's good enough for that."