Shanghai - Argentina's in-form Juan Martin del Potro survived a major scare at the Shanghai Masters on Wednesday, battling back from a set down to beat Philipp Kohlschreiber in a third-set tie-break.
The German world number 23 rattled the former US Open champion, striking 50 winners and 22 aces in a brave display of attacking tennis that had Del Potro searching for answers before he dug deep to win 3-6, 6-3, 7-6 (7/4).
Kohlschreiber was quickly out of the blocks, unveiling his full repertoire of shots including an impressive single-handed backhand, and breaking at the first opportunity, which proved enough to take the opening set.
Sixth seed Del Potro, fresh from winning his third title of the year at the Japan Open on Sunday, grabbed a foothold by breaking at the start of the second set, going onto level the match.
The 25-year-old looked to be heading for victory when he broke in the seventh game of the decider before serving for the match.
Kohlschreiber broke back, forcing the tie-break, but Del Potro held firm and progressed to the third round.
There were also wins on Wednesday for seventh seed Jo-Wilfried Tsonga, who beat Spain's Pablo Andujar 6-3, 6-2; while 16th-seed Spaniard Tommy Robredo retired from his match against Italy's Fabio Fognini with a wrist injury.
America's top player John Isner, seeded 14th, lost 6-4, 7-6 (7/4) to Argentina's Carlos Berlocq.
The likes of top seed Novak Djokovic, world number one Rafael Nadal, and Roger Federer play their first matches on Wednesday, along with the other top eight seeds, all of whom get a bye into the second round.
Drenching rains earlier in the week as a result of Typhoon Fitow forced matches indoors, but the wet weather relented on Wednesday, allowing tournament chiefs to open the roof of the stadium court.
Results on the fourth day of the Shanghai Masters on Wednesday (x denotes seeding):
Juan Martin del Potro (ARG x6) bt Philipp Kohlschreiber (GER) 3-6, 6-3, 7-6 (7/4)
Carlos Berlocq (ARG) bt John Isner (USA x14) 6-4, 7-6 (7/4)
Jo-Wilfried Tsonga (FRA x7) bt Pablo Andujar (ESP) 6-3, 6-2
Fabio Fognini (ITA) bt Tommy Robredo (ESP x16) 7-6 (7/3), 2-1 retired