Kaymer on Sunday finished the final round of the course one-under-par - and 13 -under-par for the golf tournament - widely regarded as the unofficial fifth major - itself.

The 29-year-old German clinched victory over American Jim Furyk by just one stroke in the $10-million (7.25-million-euro) event.

Kaymer had a three-shot lead by the time he lined up to putt on the 14th hole, when nearby lightning forced officials to call a weather break.

After play resumed, the former world number one from Dusseldorf appeared to experience a sudden dip in form, getting a potentially disastrous double-bogey on the 15th.

However, he was able to hold onto a narrow lead, notably making a 30-foot par putt on the 17th hole as darkness fell, before winning by one shot on the 18th.

"It is always very difficult to come back after a little (weather) break," Kaymer told Golf Channel.

"The first 14 holes, I played really, really well. And then you are really disappointed when they called it (halted play). I made a couple of wrong decisions on 15. But a big putt on 17."

"It is probably the biggest tournament we play all year, except the majors," he said. "It's a big, big trophy and a big achievement for me."

Kaymer's only other victory on the PGA Tour was a major, in the form of the German golfer Martin Kaymer wins first Major2010 PGA Championship.#

rc/crh (AFP, AP, Reuters)