MASON, Ohio -- Tommy Robredo knows a memorable match when he wins one.
He did it again Thursday, beating top-ranked Wimbledon champion Novak Djokovic 7-6 (6), 7-5 in the round of 16 at the Western & Southern Open.
The 16th-seeded Spaniard beat a top-ranked player for the second time in his career. The first time, he edged Lleyton Hewitt in the 2003 French Open.
"When I finish my career, and when I will be sitting at home and talking with friends, I will remember days like this," Robredo said.
Djokovic, who has never won the Cincinnati-area event, dropped the first set after fighting back from a 6-3 deficit in the tiebreaker. Robredo took the set with an ace that Djokovic challenged. The replay showed the ball caught the slimmest sliver of the line.
Robredo failed to convert two match points before completing the victory with a slam on Djokovic's short lob.
"It's disappointing that I'm finishing Cincinnati again with a tough loss, but it's the sport," said Djokovic, who lost in the third round at Toronto last week. "I didn't play well in Toronto, didn't play well here. Hopefully, it's going to be different in New York (at the U.S. Open)."
Robredo had lost six straight matches against the Serb after winning their first encounter.
"I knew that if I wanted to win I had to go for it and try to hope that he will not play his best match," Robredo said. "Both things happen and then I could win."
"There was some frustration, but that's what Gael does to you," Federer said. "I felt like I missed some opportunities in the second set to close him out, but that's a credit to him. He hung in there."
Earlier, Andy Murray fought off two match points and edged John Isner, 7-6 (3), 6-4, 7-6 (2) before a standing-room-only crowd on the grandstand court next to Center Court. Fans standing at the top of the main court could be seen watching Isner and Murray.
"I had lost a few close matches -- matches like that -- over the last few months, so it was important for me to come through," Murray said, a two-time W&S champion. "You know, it was completely packed crowd from the first point right until the end, as well. So it was a really good atmosphere to get ready for the rest of the tournament, but also the U.S. Open, as well. It was very good."
Isner, who lost to Rafael Nadal in last year's final, had two chances to win the match with a 6-5 lead in the third set, but Murray salvaged both points before taking control with a mini-break for a 3-1 lead in the tiebreaker.
Despite losing, Isner considered the match his best of the hard-court season.
"This year, for sure," he said. "I knew it was going to be a good match. I mean, I didn't imagine myself blowing him off the court, and vice versa, I didn't imagine him blowing me off the court."
Stan Wawrinka shook off losing the first set to roll through the next two and advance with a 3-6, 6-0, 6-1 win over Marin Cilic. Wawrinka, the Australian Open champion, will meet unseeded Julien Benneteau in the quarterfinals. Benneteau eliminated Jerzy Janowicz 7-5, 6-1. Fabio Fognini also needed three sets to get past Yen-hsun Lu, 3-6, 6-3, 6-3, and Milos Ranoic held off wild-card Steve Johnson 6-7 (6), 6-3, 7-6 (4).
Serena Williams immediately took command, breaking Pennetta's first serve of the match.
"I got the early break, and I didn't let go," she said. "That's what I wanted to do. She can try and come back. She tried to come back, I wanted to stay focused."
Halep and Maria Sharapova will meet in the quarterfinals -- a rematch of the French Open final won by Sharapova. The fifth seed advanced with a 6-4, 7-6 (2) win over Anastasia Pavlyuchenkova. Jelena Jankovic also moved on with a 7-6 (4), 6-4 victory over Sloane Stephens, and Ana Ivanovich advanced with a 6-2, 2-6, 6-3 win over Svetlana Kuznetsova. Agnieszka Radwanska routed Sabine Lisicki 6-1, 6-1.