SECOND-ROUND LEADERBOARD:-7 T Woods (US) -3 V Singh (Fij), B Jones (Aus), L Glover (US), R Fisher (Eng), P Harrington (Ire) -2 I Poulter (Eng), L Westwood (Eng) Selected others: -1 E Els (SA) Level R McIlroy (NIre) +1 G McDowell (NIre), A Quiros (Spa) +2 O Wilson (Eng) +4 Phil Mickelson (US)
Woods has won all eight majors when leading at halfway
Tiger Woods made an emphatic statement of intent with a round of 70 to open up a four-shot lead at the halfway stage of the USPGA Championship at Hazeltine.
The world number one climbed to seven under and beat off the challenges of Padraig Harrington and Ross Fisher to stamp his authority on the tournament.
Harrington and Fisher both fell back into a tie for second alongside Vijay Singh, Brendan Jones and Lucas Glover.
Lee Westwood and Ian Poulter finished two under with Ernie Els one back.
But the day belonged to Woods, who is chasing a 15th major title and a record-equalling fifth USPGA crown.
The 33-year-old, the overnight leader by one, was joined at the top at various stages by Harrington, Fisher, Graeme McDowell and Alvaro Quiros, but despite bogeying the opening hole he remained resolute as his challengers fell away.
"It was a tough day all around. The wind was blustery, the greens a little bumpy," said Woods.
Woods birdied the 6th and 7th and dropped a shot at the 10th but a run of three straight birdies from the 14th gave him a four-shot lead up the last. A scrappy closing bogey was matched by one from Harrington, giving Woods a huge cushion for the weekend.
Eight times he has led a major at halfway and eight times he has gone on to win.
"In order to have a lead in a major championship, you can't be playing poorly," said Woods. "All those times, I've been playing well. And I'm playing well now.
"There's a long way to go, 36 holes. I'll just keep plodding along."
Fisher was six under for the round before bogeying the final two holes
Fisher, 28, was the last to challenge Woods after charging to six under for his round through 16, but bogeys on his last two holes put out the fire, despite a still-impressive 68.
"In some ways I'm disappointed, but overall delighted," said Fisher. "I felt like I hit the ball fantastically well today.
"At the same time, to finish bogey, bogey always leaves a little bit of a sour taste. But I'm still in there with a good shout with 36 to go."
Defending champion Harrington was last level with his playing partner after the 10th but he faltered with three dropped shots from the 11th and another on 18, either side of birdies on 14 and 15.
"I'm a little bit disappointed with the finish. I struggled in the middle of the round," said Harrington, who has partnered Woods for his last three rounds stretching back to the WGC at Firestone.
Lee Westwood mounted a mid-round charge and four birdies in seven holes from the 9th got him to four under, but a double bogey on the 17th also let Woods off the hook.
Singh, Jones and US Open champion Glover all completed their rounds in the kinder morning conditions, and it will be Fiji's two-time former champion Singh, as the first to post three under, who partners Woods at 1940 BST in round three.
Poulter's early round of 70 saw him creep up the leaderboard as a stiffening breeze and bumpy greens kept the afternoon scoring in check.
McDowell climbed into a four-way tie with Woods, Harrington and Quiros with two birdies in his first five holes but he fell away to a 75 for one over.
The big-hitting Quiros also plummeted from view with five bogeys also dropping him to one over.
World number two Phil Mickelson, out of practice after caring for his wife and mother who have breast cancer, struggled with his putter en route to a 74 for four over to make the cut on the mark.
"I'm not going to beat many people putting the way I am," Mickelson said. "I've got to get this thing turned around.
"I don't feel like I'm striking it horrendously. It's just I'm having trouble scoring right now."
England's Luke Donald also made the cut with no room to spare after a birdie on 18, but Sergio Garcia and Justin Rose (both five over) both missed out.
Others making an early exit were Colin Montgomerie (+9), Darren Clarke (+10) and Nick Dougherty (+11).