Bothered by back, Federer loses U.S. Open quarterfinal to Dimitrov

New York • Betrayed by his 38-year-old body, and his forehand, Roger Federer is done at the U.S. Open.Federer’s upper back and neck gave him trouble, he kept missing makeable shots and he kept giving away the lead against a guy he’d never lost to. It all added up to getting beaten 3-6, 6-4, 3-6, 6-4, 6-2 by 78th-ranked Grigor Dimitrov in the quarterfinals before a stunned crowd at Arthur Ashe Stadium on Tuesday night.“Grigor was able to put me away,” Federer said. &