The incomparable Tiger Woods gave yet another golfing masterclass in Chicago yesterday, leaving Luke Donald and the rest trailing in his wake as he claimed his 12th major title.

Donald, joint leader with a round to go and in contention for a major for the first time, was simply powerless to prevent the world number winning the US PGA championship at Medinah.

Woods' dominance was such that by the back nine his only challenge was to try to achieve the lowest score under par in the history of the majors - all 399 of them.

A bogey on the short 17th denied him that, but 18 under matched the PGA record he and Bob May set six years ago. And this time, thanks to a closing 68, it gave him a five-stroke victory over 2003 winner Shaun Micheel.

It was the world number one's second successive major and his third tournament win in a row. And it puts him second on his own in the all-time list, just six behind Jack Nicklaus.

Woods, 30, has now won 12 of the 40 majors he has played as a professional. It took Nicklaus 48 to get to the same point.

This was the 12th time out of 12 that Woods has turned at least a share of top spot entering the final day into victory. And, as at the Open last month, he made it look a piece of cake.

Donald had not had a bogey for 36 holes going into their duel in the sun, but that soon changed and he was already out of it when another came at the long 10th. He did not manage a single birdie, in fact, in slipping to joint third place with Sergio Garcia and Adam Scott.

That should seal Ryder Cup spots for Garcia and Donald, while Ian Poulter's ninth place keeps his hopes alive with two events to go.

Woods turned it into a one-man show like so often before, sinking two putts of over 30 feet as he raced to the turn in 32 to be four clear.

The gap - make that chasm - widened to five when he made a 10-footer on the 11th despite having driven into the rough.

Donald had hoped to become the first European to win a major since 1999 and the first to win this title since Tommy Armour in 1930. But doing it playing with Woods in the final group was never a good situation to be in to try to make it happen.

His bogey-free run ended after he unluckily drove into a divot hole on the fourth and when he missed a three-footer at the next there was a sense already that it was just not going to be his day.

As for the American Ryder Cup race, Steve Stricker became the only player in with a chance of forcing himself into the top 10 in this their final counting event.

He had to climb from 12th to third in the championship on the final day and with three to play was up to sixth, probably needing two more birdies to have a chance. But he could not do it and Brett Wetterich clung on to the last automatic spot.

Captain Tom Lehman already has four uncapped players in his side - Wetterich, Vaughn Taylor, JJ Henry and Zach Johnson - and is expected to add some more experience with his two wild cards tomorrow.

Stewart Cink and Davis Love are the favourites in that order, but there was speculation that Lehman was considering his assistant Corey Pavin.

Meanwhile, a concerned David Howell gave Europe's Ryder Cup camp a worry by revealing that he had come close to pulling out of the event.

With less than five weeks to go to the Ryder Cup Howell, who leads the points race, crashed to an horrific 82 after suffering a shoulder problem warming up.

Graeme McDowell carded a final round 72 to finish on one under while Padraig Harrington missed the cut.