Shaken by his shocking US Open quarterfinal loss to Tomas Berdych, world No 1 Roger Federer is going "back to the drawing board" to try to pick up the pieces of a suddenly shattered season.

"I've got to go back to the drawing board from here and see what's really a priority," Federer said. "I'm disappointed. I really expected myself to play better."

Federer saw his 21-match unbeaten run in night matches at Arthur Ashe Stadium snapped by a rival whom he had beaten in 11 of 15 prior meetings, one who had never played a night match in the largest Grand Slam tennis venue.

After collecting his first Grand Slam title in 2 1/2 years by beating Murray in the Wimbledon final, taking an Olympic silver medal and reclaiming the world No 1 ranking, Federer was handed his worst US Open loss since a fourth-round ouster in 2003 by David Nalbandian.

"The goal has been achieved, but now this is disappointing for me," Federer said. "We'll see where I go from now and if I go to Davis Cup or not, about what's to come for the remainder for the season."

Fighting for the season-ending world No 1 spot will play a role in his decision once the sting of defeat has eased. "No 1 has another role to play," Federer said. "But this obviously is a setback."

Federer was trying to become the first man in 87 years to win a sixth US Open and capture his 18th career Grand Slam title. Instead, he missed out on what would have been a 33rd Slam semi-final and ninth in a row in New York.

(China Daily 09/07/2012 page24)