Del Potro tops Mayer, returns to U.S. Open 4th round

Juan Martin del Potro closed out countryman Leonardo Mayer in a 20-point tiebreaker, which included a shot by Mayer that bounced off the net post while seemingly headed wide and landed in, to return to the fourth round of the U.S. Open for the first time since his 2009 title run.

The seventh-seeded Argentine won 6-3, 7-5, 7-6 (9) in 3 hours, 20 minutes Sunday. Del Potro was unable to defend his championship in 2010 because of right wrist surgery. Last year, he lost in the third round.

At 8-8 in the third-set tiebreaker, Mayer lunged for a ball deep in the corner and his backhand appeared to be sailing wide. But it ricocheted off the top of the post and redirected, touching down in the middle of the court, where del Potro knocked the ball back with a forehand. Mayer couldn't capitalize on the fluky play, though. On his next shot, he hit a backhand long, then leaned back, a hand to his head as he laughed, amazed and frustrated at the same time.

Del Potro said he had never seen a bounce like that. He suggested Mayer's shot might have clipped the line for a winner if it hadn't hit the post.

"Was unbelievable point, really important point," del Potro said.

Indeed, it gave del Potro his fifth match point. Mayer saved it, but del Potro finally clinched the victory on his sixth at 10-9, hitting a big serve that Mayer returned long.

Del Potro is coming off a bronze medal at the Olympics, defeating Novak Djokovic in the third-place match in London.

The 63rd-ranked Mayer has never reached the fourth round at a major tournament or defeated a top-10 player. He had 11 aces and 44 winners but 45 unforced errors.

Del Potro next faces another former U.S. Open champ, 2003 winner Andy Roddick, who will retire after his run here ends. The crowd will undoubtedly be looking to will the American to an upset victory to extend his career.

"I know this is special, this day, for him, but I'm doing my job," del Potro said. "I will try to be focused on my match and doing my things, my shots. The match is going to be very tough. But if I play in high level, will be tough for both players."