Woods opened his account in the final major of the year with a bogey-free, five-under-par 67, while Harrington, the defending US PGA champion,
shot a 68 to throw down the gauntlet to the afternoon wave of starters including world No.2 Phil Mickelson, and 2009 major winners Angel Cabrera, Stewart Cink and Lucas Glover.

“The golf course is set up very fair,” Woods said. “It’s difficult but as Paddy [Harrington] and I were saying, you don’t [usually] see pins, six, seven, eight feet from the side. It’s normally three and four. So you can be a little more aggressive going at these flags.”

Having gone head-to-head at Firestone Country Club last Sunday in the final round, Woods and Harrington were paired once more for the first two rounds alongside Rich Beem, the 2002 champion when the event last visited Hazeltine.

A triple-bogey from Harring­ton last Sunday had decided their battle and handed Woods his fifth victory of the year and the world No.1, a four-time US PGA champion, began the quest for his 15th major looking for a third tournament win in as many weeks. The pair matched hole-for- hole initially, both sinking birdies at their third hole of the day, the 12th, the Irishman thanks to a great approach shot to six feet and Woods with a 25-foot putt.

Woods stole a march on the 642-yard, par-5 15th, getting up and down from a bunker but at the next hole Harring­ton caught up, thanks to another good iron shot to six feet.

Harrington had his first stutter of the day when he bogeyed the first, his 10th hole, but bounced straight back with a birdie at the next to return to two under. Woods also birdied the second to move to three under but was still lying one shot off the lead as Australia’s Robert Allenby, American Michael Bradley and Alvaro Quiros all improved to four under.

Allenby birdied the 14th, Bradley the eighth and the Spaniard made a 3 at the par-4 second but then all three dropped shots and Woods and Harrington pounced.

Woods was the first to get to four under, with a birdie at the third, his 12th, and Harrington joined him there thanks to another good iron shot at the sixth, from where he made a birdie 3. Harrington missed a
birdie chance at the seventh but Woods, having left his eagle putt short, made no mistake from three feet to go into the outright lead at five under, parring his way home to the clubhouse lead in 67.

“The great thing when you play with Tiger is that you know you’re going to have to play the shots,” Harrington said. “It puts you under more pressure and you feel like you might as well go after it rather than hang back.”

Hunter Mahan, the US Ryder Cup player, could have joined Harrington at four under but closed with a bogey 5 at the ninth for a three-under 69 in the clubhouse alongside Australia’s Allenby and Mathew
Goggin and Quiros.

Lee Westwood had an eventful opening nine holes starting at the 10th. The world No.13, who tied for third place at last month’s Open Championship, bogeyed his third and birdied the fourth then bogeyed the 16th and birdied the 17th to get back to even par as he made the turn.

He moved to two under thanks to birdies at the fifth and seventh and closed with a two-under 70, as did Northern Ireland’s Graeme McDowell.

Northern Ireland’s Rory McIlroy got his US PGA debut up and running with a one-under-par 71, as did Spain’s Sergio Garcia.

World No.3 Paul Casey withdrew early yesterday morning due to a rib injury, his place in the 156-man field taken by American Tim Petrovic.