INDIAN WELLS, CALIFORNIA // Novak Djokovic extended his winning streak to 15 matches with a 6-0, 6-1 victory over fellow Serb Viktor Troicki in the fourth-round of the BNP Paribas Open.
Djokovic, ranked third in the world, has lost just six games in his first three matches at Indian Wells, where he won the 2008 title. Djokovic's perfect match record this year includes winning titles at the Australian Open and Dubai, where he beat Roger Federer in the final.
Troicki, the 16th seed, had not lost a set here until he ran into Djokovic on a day when temperatures in the desert soared to near 90 degrees — 10 to 15 degrees warmer than usual for the second straight day.
Troicki came into the match with a 14-5 record, but Djokovic dominated from the beginning in winning for the eighth straight time against him. Djokovic's last defeat came in November against Federer in the ATP World Tour finals in London.
Djokovic and Troicki later teamed up for a doubles match and lost.
Eighth-seeded Andy Roddick fought his temper and No 18 Richard Gasquet, losing 6-3, 7-6. It was Gasquet's second win over a top-10 player this week, having taken out the No 10 Jurgen Melzer in the third-round.
"He outplayed me from the first ball. He was obviously very confident," Roddick said. "I tried to force it and be more aggressive in the second, but when you play that way, it starts coming in bunches. You win in bunches and you lose in bunches."
Roddick argued with the chair umpire when he trailed 3-1 in the second set, telling the umpire he was giving him a warning of his own. He rallied to lead 6-5 before a backhand error allowed Gasquet to force the tiebreaker.
"With the mistakes he made, it's only fair that I would give him a warning," Roddick said. "I only made one mistake. I only broke one racket. He missed a couple of calls, so I feel like it was a little presumptuous of him to give me a warning off one broken racket."
Roddick fell behind 5-2 in the tiebreaker, tossing his racket when Gasquet hit a winner into the corner off his drop shot. Roddick rallied again, hitting a forehand winner on the run to get to 5-5. Gasquet got to match point, with Roddick's first serve just missing. The Frenchman hit a backwinner off his second serve to close out the match.
Juan Martin del Potro beat his third seeded player, this time taking out the No 32 Philipp Kohlschreiber 7-6, 7-6.
Del Potro, from Argentina, improved his match record to 17-4 this year as he rebounds from an injury-marred 2010. He has surged from No 484 to 90th in the world rankings in a three-week span, winning a title at Delray Beach and reaching the semi-finals in two other tournaments.
"I am playing better than two months ago. I know it's a long road, but I'm still improving my serve, my forehand," he said. "It's very tough to play every day against these kind of players, and I need time to feel 100 per cent again."
Now, Del Potro is into the quarter-finals, where he will play the 25th-seeded Tommy Robredo of Spain. Robredo beat the No 21 American Sam Querrey 6-1, 6-3.
Robredo was hobbled by a leg problem at 2-2 in the second set in his match against Querrey. He first got treatment on his leg two weeks ago.
"I felt something there and then it was very tough for me to play," he said. "Luckily, I could win. I have one day to recover and hopefully I can go through."
Against Kohlschreiber, Del Potro called for a trainer in the middle of the first set.
Del Potro rallied after trailing 6-1 in the second-set tiebreaker, and won with an ace on his third match point.
No 7 Tomas Berdych lost in three sets to Stanislas Wawrinka, and No 23 Albert Montanes fell to Ivo Karlovic.
No 15 Marion Bartoli, the highest seeded woman in action, ended Ana Ivanovic's run with a 6-4, 7-6 quarter-final victory. Ivanovic had not dropped a set until her loss.
Bartoli advanced on Tuesday when Kim Clijsters withdrew from their match because of a shoulder injury. The Frenchwoman was not feeling well herself on Wednesday, overcoming a stomach virus that kept her from eating breakfast before the match.