Del Potro, Simon reach Open 13 quarterfinals
Del Potro had 14 aces and saved nine of the 10 break points he faced as he was pushed all the way by the veteran Frenchman in a rematch of last year's final.
"It was very, very tough. It shows the level of the tournament is so high," del Potro said. "I think I played a very good level at the end of the match. He played well throughout the match. I needed luck to beat him today, because he deserved to win the match as well."
The 2009 U.S. Open champion faces another Frenchman, Gilles Simon, in the quarterfinals after he advanced to his third straight quarterfinals with a 6-3, 6-1 win against Roberto Bautista-Agut, although Simon's serve was again not at its best. He broke his Spanish opponent seven times, but conceded three breaks of his own.
Tursunov, a semifinalist at the tournament two years ago, saved the four break points he faced and twice broke the Serb. He next plays Gilles Muller of Luxembourg.
Copyright 2013 by The Associated Press
This story is from ESPN.com's automated news wire. Wire index
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