GRAND BLANC, Mich. (AP) Whatever Tiger Woods has been doing since losing a chance to win the Grand Slam is working.

Woods shot a 9-under 63 Friday - his best round since last year's Byron Nelson Classic - and pulled away from the field with a four-stroke lead after two rounds of the Buick Open.

"My swing is coming together, I'm making progress," he said. "It's not like I was struggling, but it's good to see light at the end of the tunnel."

If only his competitors - especially those who have shot in the 60s in both rounds - could say the same thing about trying to catch Woods.

At 10 under are Scott Verplank, who shot a 65, and J.J. Henry, who was 5 under for the second straight day. Verplank's first win as a professional was the Buick Open in 1988.

Verplank joked that the only way to stop Woods is to hurt him.

"Nothing I can do, unless you know, one of you guys gives me like a crow bar and you broke his legs," Verplank said in jest.

Woods has won 15 of 19 tournaments he has led or been the co-leader of after 36 holes, but he is not ready to count the Buick Open as his 33rd victory on the PGA Tour and fourth this year.

"You can't go out there and sit around and shoot a couple of 70s out there and know that the tournament is over," he said.

Woods, who began the day two strokes behind Kent Jones, had five birdies on the front nine and two birdies and an eagle on the back. He has gone 51 holes without a bogey, dating to the third hole of the final round of the British Open, where his chance at the Grand Slam ended on the third leg.

The last major, the PGA Championship, is next week at Hazeltine in Minnesota. Woods appears ready, although he insisted for the second straight day that he's not using the Buick Open as a warmup.

"If I am going to go out there and shape shots for next week, I do that on the range," Woods said. "When I am out there playing, I am trying to win."

After the round, Woods was just about the only player on the range at one end, tucked behind a tent.

Woods, who has won seven of the last 12 major tournaments including this year's Masters and U.S. Open, has a chance this week and next to add to his impressive resume.

If he wins the Buick Open and the PGA Championship he would be the first player to win three majors in one year twice. Ben Hogan did it in 1953 and Woods did it two years ago.

No one has won a major after winning a tournament the previous week since Lee Trevino captured the Canadian Open and the British Open in consecutive weeks 31 years ago.

"I never read that one, but yeah, it would be nice," Woods said.

Woods' most-impressive performance on Friday came at No. 16.

His drive landed in the right rough and was 266 yards from the pin. His second shot went around a tree and onto the green, then he made a 6-foot putt for eagle.

"It was just a cut 2-iron," he said nonchalantly.

Woods is playing in the Buick Open the week before a major for the fourth time.

In his previous three visits to Warwick Hills, he finished tied for eighth in 1997, tied for fourth in 1998 and tied for 11th in 2000 before going on to win the PGA Championship as the third leg of his "Tiger Slam."

Woods won all four majors consecutively, but not in the same calendar year. The Masters was the only major he didn't win in 2000.

The Buick Open is one of three tournaments Woods played in at least three times without winning. The other two are the Nissan Open and Phoenix Open.

"There have been a lot of great players that have won here and I would like to have my name on that list," he said.

Six lesser-known players - Jones, Pat Bates, Rod Pampling, Glen Day, Esteban Toledo and Carlos Franco - were at 9 under. Among the group, Pampling is highest on the money list at 95th, and Franco is the lowest at No. 133.

There are eight players at 8 under, including Jim Furyk and defending PGA Championship winner David Toms.

Phil Mickelson, the second-ranked player in the world, was 2 under Friday and will enter the weekend at 5 under.

Hal Sutton, who began the day 5 under, shot a 4-over 76 on Friday to miss the cut by one stroke. Other notables who missed the cut were Jerry Kelly, who is fourth on the money list, Lee Janzen, Jose Maria Olazabal and Gary Nicklaus.

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