(Reuters) - Clutch putting and a final four-birdie flourish helped Jordan Spieth transform what might have been a 75 into a remarkable two-under-par 68 in Thursday's opening round of the WGC-Bridgestone Invitational in Ohio. The American world number two produced dismal form from tee to green, especially on his front nine where he hit just one green in regulation, but he "did a great job mentally" as he made par putt after par putt to work his way into contention. Spieth's fortunes improved markedly after the turn and he reached six of nine greens in regulation before capping a round to remember with birdies on his last four holes at Firestone Country Club in Akron. More...