By losing against Croat Ivo Karlovic, Roger Federer could lose his number one place before the end of the tournament in favour of Rafael Nadal. The Spaniard beat Tommy Haas in two sets (6-4, 7-6), comforting his lead.
Rafael Nadal shifted into position to seize the No. 1 ranking with a 6-4, 7-6 (7/0) defeat of Tommy Haas only hours after Roger Federer opened the door with a Cincinnati Masters defeat.
In the wake of his Thursday third-round win over the German, Nadal stands three victories away from taking the ATP top spot from Federer. If he claims the title on Sunday, the deal is sealed.
Croatia's Ivo Karlovic defeated Federer 7-6 (8/6), 4-6, 7-6 (5/7) to open the door to the change at the top after four and a half years of Federer's reign.
Nadal, who defeated the 26-year-old Swiss in an epic Wimbledon final and won a fourth Roland Garros title, has been chasing Federer all season.
The 12-time grand slam winner has owned the top ranking for 235 weeks, fourth longest in the record books.
"It's disappointing, losing without getting broken, but it's not the first player it has happened to, especially to a guy like Ivo," Federer said after losing the first match in his career where his service was never broken.
"There's always danger in tough matches against Ivo. I knew that from the start."
Federer has no choice but to look ahead to the Beijing Olympics opening next Friday.
"So far it's OK," Federer said. "I guess I'll analyse and assess my game after the US Open.
"For the moment it's just all a blur. So many tournaments in a row, big tournaments in a row, it's hard.
"It's a tough trip we've got up in front of us now, going back to China and coming back to the Open.
"I'm looking forward for the next two tournaments. Those are really the ones that can make this season from a good one to a great one again. I hope I can manage to pull off something in the next couple of weeks."
Novak Djokovic and Ernests Gulbis set up their second battle in as many months by reaching the quarter-finals while Scot eighth seed Andy Murray put out Russian Dmitry Tursunov 6-3, 6-3.
Third seed Djokovic, riding his best run of form in the steamy American midwest, swamped his second straight Italian opponent as he crushed Andreas Seppi 6-1, 6-2 a day after beating Simone Bolelli in two tie-breakers.
Serbian Djokovic, 21, and Latvian teenager Gulbis hung out as kids when they attended the tennis academy of Niki Pilic in Munich.
Gulbis reproduced his French Open form over luckless James Blake, sending the veteran US seventh seed down to a 6-4, 1-6, 6-3 upset.
"I haven't played against top 10 players so much in my career, so beating one of them gives me more confidence," said the world number 53, who still seeks his first career ATP final.
"I knew that he's a tougher opponent on hard court than he is on clay, so I was a little bit nervous, but as the match went on I played pretty well in the beginning, though I lost my concentration in the second set."
Date created : 2008-08-01