* Isner stuns top seed Djokovic in three sets
* Djokovic misses chance at Golden Masters
* Berdych has Murray's number once again (Updates with Murray loss)
CINCINNATI, Aug 16 (Reuters) - World number one Novak Djokovic and number two Andy Murray crashed out of the Western and Southern Open within an hour of each other on Friday, creating shockwaves that will carry through to the U.S. Open.
With the sprawling Lindner Family Tennis Center still buzzing over John Isner's 7-6 (5) 3-6 7-5 upset of Djokovic, another bombshell dropped on the nearby grandstand court as Tomas Berdych swept past U.S. Open champion Murray 6-3 6-4.
The upsets of two of the big favourites for the U.S. Open, which gets underway in Flushing Meadows on Aug. 26, has thrown the year's final grand slam wide open, adding a few more contenders to the list of usual suspects.
American Isner and Czech Berdych can now be pencilled in to join Djokovic, Murray, Rafa Nadal and Roger Federer, who between them have lifted 33 of the last 34 grand slam events.
In a heavyweight matchup featuring two of the game's big-hitters, it was Isner who came out on top after a slugfest lasting two hours and 23 minutes to set up a meeting in the last four with Argentine Juan Martin Del Potro.
Djokovic, a four-time runner-up on the Cincinnati hardcourts, had been eager to take the final step this year and become the first player to complete what the ATP Tour has dubbed the Career Golden Masters by winning all nine World Tour Masters titles.
But Isner, the top-ranked American at 22 who has been in good form on hardcourt surfaces with a win in Atlanta and a runner-up finish in Washington, signalled right from the start that Djokovic was in for a fight.
"I was putting the ball on the court and I was feeling good off the baseline, I felt like, when I had a chance. I played aggressively," said Isner, who also got the better of the Serb last year with a semi-final win at Indian Wells Masters.
"I think I was able to put a little bit of pressure on him. These hardcourts are surfaces that I enjoy playing on. Not only that, I'm playing in the States. My record in the U.S. compared to outside the U.S. is shockingly different."
The two men set a pounding tone for the match in a 47-minute opening set that went to a tiebreak with the American prevailing 7-5.
Facing a triple set point, Djokovic was able to fight off two but on the third he slammed a return into the net, giving Isner the early advantage to the delight of the partisan home crowd.
STEPPED UP PRESSURE
Djokovic stepped up the pressure in the second set, breaking Isner at the first opportunity on the way to a 3-0 lead before leveling the match.
But Isner was eager for the fight, coming back in the third and breaking Djokovic to cap the upset.
Murray said he struggled to come to grips with the fast surface but the sixth-seeded Berdych was always going to represent a tricky test for the Wimbledon champion with the Czech holding a slight 5-4 advantage in head-to-head meetings.
The Scot, a two-time winner in Cincinnati, had just four break chances against Berdych and failed to convert them all.
"You know, the things that I really need to do well - serving, returning, moving - that was good," said Murray. "But I'll need to work on my groundstrokes a bit, make sure I'm not making too many mistakes going into the U.S. Open.
"Today when I had my opportunities, you know, I didn't take them. That was the problem today."
Del Potro, the 2009 U.S. Open champion, continued to sharpen his hardcourt game before heading to Flushing Meadows, beating Russian Dmitry Tursunov, the first qualifier to reach the last eight in Cincinnati in 11 years, 6-4 3-6 6-1.
"Trying to play slices and different shots in this tournament before the U.S. Open to see how different I can play against the top guys or doing different things," said Del Potro.
"It's the last tournament for me before the U.S. Open, so it means a good thing to close my preparations to get there." (By Mark Lamport-Stokes)