Andy Roddick's fourth-round match against Juan Martin del Potro at the U.S. Open was suspended because of rain and is scheduled to resume Wednesday.

Play was halted right after Roddick went ahead 1-0 in a first-set tiebreaker Tuesday night. A little more than a half-hour later, the tournament called off play for the day.

Roddick, the 2003 champion at Flushing Meadows, announced last week the U.S. Open will be last tournament of his career.

He appeared on his way to a definitive first set victory, but del Potro — the 2009 tournament champion — rallied from a 5-2 deficit.

Other matches stopped in progress, also in the first, included defending champion Novak Djokovic against No. 18 Stanislas Wawrinka, and No. 8 Janko Tipsarevic against No. 19 Philipp Kohlschreiber. Earlier, four-time major champion Maria Sharapova's quarter-final against No. 11 Marion Bartoli was pushed to Wednesday, with Bartoli leading 4-0.

Top-ranked Victoria Azarenka got her match completed, pushed to the limit by defending champion Sam Stosur before winning in a third-set tiebreaker in the quarters.

Azarenka eked out a 6-1, 4-6, 7-6 (5) victory in 2 hours, 23 minutes — not including an early 76-minute rain delay. She had never lost even a set to the Australian in six previous meetings, but Stosur rallied time and again after a lopsided first set.

"She played amazing," Azarenka said. "So much higher, the level was today. Again made me play my best tennis. I was hoping for a few outs, but she kept hitting the lines. ... I kept saying, 'Miss, miss.' She didn't want to, I guess."

Azarenka next plays either Sharapova or Bartoli.

The seventh-seeded Stosur came back from down a break twice in the third set. Then in the tiebreaker, she recovered from trailing 4-0 to tie it at 5.

Azarenka, the Australian Open champ from Belarus, never wavered. Her final forehand touched down on the baseline, forcing Stosur into a wild backhand.

"I have no words," Azarenka said. "I think we both showed some excellent tennis. You could feel the pressure all the time. We really both gave it all and we fought really hard, [kept] making each other run like crazy."

Azarenka improved to 11-0 in three-set matches this year. She had never before made it past the fourth round at the U.S. Open. Azarenka kept Stosur on the run in the first set, breaking her three times. But in the second, Stosur started channeling the aggressive play that allowed her to upset Serena Williams in the final here last year, pounding big forehands for winners.

In a men's fourth-round match, David Ferrer and Richard Gasquet were stopped by rain in the late afternoon in the third set with the fourth-seeded Spaniard leading 7-5, 7-6 (2), 4-3.

Ferrer finished matters off just after 8 p.m. ET, winning the final set 6-4. His quarter-final opponent will be the surivor of  the match between Tipsarevic and Kohlschreiber.