Tiger Woods joked after struggling to a four-over-par 75 in the first round at the Northern Trust in New Jersey on Thursday that at least he had broken 80. The score, which left him 13 strokes behind American leader Troy Merritt, was the latest indication that all is not well with the 15-times major champion's surgically-fused spine. Woods had acknowledged that his back was stiff on the eve of the first event of the PGA Tour's FedEx Cup playoffs. "It's still a little bit stiff, but that's just the way it's going to be," he told reporters after a round that bettered only two players in the 120-man field at Liberty National. Merritt shot 62 to lead compatriot Dustin Johnson by one shot on a day when all the good scores came in the morning, before a breeze sprang up and made for a sterner test on the waterfront course within sight of Manhattan and the Statue of Liberty. Nobody shot better in the afternoon than the 65 by Englishman Justin Rose. Irishman Shane Lowry, in his first start since winning the British Open, managed a 69 in the morning, a shot better than world number one Brooks Koepka. Woods, on the other hand, could barely have made a worse start, four over par after nine holes, before somewhat steadying the ship on the back nine. "I didn't hit any good shots and didn't make any putts. Other than that it added up to a round that broke 80," he said. "The driver felt fine but I just didn't feel sharp with anything else. My iron game, which is usually the strongest part of my game, was off ... my distance control was off." Since ending a decade-long major drought by winning the Masters four months ago, the 43-year-old Woods has barely played outside the majors and has not impressed when he has competed. He entered this week's event ranked 28th in the FedEx Cup rankings, not yet assured of advancing in a fortnight to the season-ending Tour Championship, where he won last year in a rousing performance that set the stage for his Masters triumph. "I'm going to have to figure out a way to get this thing under par (on Friday)," he said. -Reuters