CHASKA, MINN. ? Three players took turn sharing the lead with Tiger Woods until he stood alone at the PGA Championship.

The final hour at Hazeltine changed everything.

Woods fired off three straight birdies, which began with a drive onto the fringe of the 299-yard 14th hole.

He finished with a 2-under 70 to build a four-shot lead, his largest through 36 holes at a major since the 2005 British Open at St. Andrews, when he led by five.

Woods is 8-0 when leading a major through 36 holes, and his chances only improved as everyone around him faltered.

“In order to have a lead in a major championship, you can’t be playing poorly,” said Woods, who was at 7-under 137. “And all the times that I’ve been in this position, I have played well. And I’m playing well now.”

Ross Fisher was the last challenger to crumble. Tied for the lead with two holes to play, he came up woefully short on the par-3 17th and hit a drive that left him an awkward stance in the sand, both shots leading to bogey and a 68. Padraig Harrington was tied with eight holes to play until he made three straight bogeys, closing with another bogey when he missed a 31/2-foot putt. He finished with a 73.

Before them was Graeme McDowell, who couldn’t keep the ball dry and wasted a good start by shooting 75.

Fisher and Harrington finished four shots behind at 3-under 141, along with Vijay Singh (72), U.S. Open champion Lucas Glover (70) and Brendan Jones (70), who played in the morning when the greens were at their smoothest, though still not easy.

“I mean, yes, Tiger is the greatest golf I think we’ve ever seen,” Fisher said. “But at the end of the day, he’s just like me and you. He’s just a human being. So we’ve got to work really, really hard to try and compete with him and catch him.”

Woods has not lost a 36-hole lead on the PGA Tour in five years, dating to the Byron Nelson when he was revamping his swing. He came to Hazeltine having won his last two tournaments, however, and appears to be hitting his stride.

Phil Mickelson again struggled on the greens, particularly the short putts that could have kept his round going. He wound up with a 74 for the second straight day, the first time he has failed to shoot par or better in the opening two rounds of the PGA Championship. Only late in the day, as the greens turned bumpy, did he make the cut on the number at 4-over 148.

BASEBALL

Red Sox add SS Gonzalez

Cincinnati — The Boston Red Sox tried to boost their infield Friday, reacquiring shortstop Alex Gonzalez and cash from the Cincinnati Reds for minor-league infielder Kris Negron. The 32-year-old Gonzalez played for Boston in 2006, hitting .255 with 50 RBIs and setting a team record for shortstops with a .985 fielding percentage.

Beltran to test knee

New York — Mets center fielder Carlos Beltran is expected to shag fly balls again today in an effort to test his bruised right knee. If everything goes well, Beltran could try running the bases before going on a minor-league rehab assignment. The All-Star slugger has been on the disabled list since June 22 because of a bone bruise on the knee.

COLLEGE FOOTBALL

NCAA looking at Sooner LB

Norman, Okla. — The NCAA has decertified the eligibility of Oklahoma linebacker Mike Balogun, who joined the Sooners last season after playing semipro football.

Balogun, 25, can practice through Wednesday. Coach Bob Stoops says he may not be eligible to play after that. The NCAA is reviewing whether Balogun participated in any games with the North American Football League after the age of 21. According to the school, such participation could result in lost eligibility.

Pregame handshakes set

College football teams are planning to start the season off on a courteous note. As part of a sportsmanship initiative, the American Football Coaches Association and NCAA are encouraging schools to arrange teamwide handshakes on the field before kickoff.

Grant Teaff, executive director of the AFCA, says college football players and teams are in a pressure-packed environment and that encouraging respect and sportsmanship is important.

Coaches are required to shake before and after games, but having players do it in an organized way is new. The handshake is only planned for the first week of games, and is not mandatory, though Teaff says all schools have been asked to participate.

COLLEGE BASKETBALL

Cremins signs extension

Charleston, S.C. — Bobby Cremins is sticking around at the College of Charleston. The school said on Friday that Cremins signed a two-year contract extension that keeps him with the Cougars through the 2013-14 season.

Alaska field trimmed

Anchorage, Alaska — There will be a smaller field of men’s basketball teams for the 2009 Great Alaska Shootout. It was announced Friday that six teams instead of the traditional eight will comprise this year’s tournament, scheduled for Nov. 24-28 in Anchorage.

Pitino plot claimed

New York — The woman accused of trying to extort as much as $10 million from Rick Pitino over a sexual encounter says the Louisville coach orchestrated a plot to keep her silent, including a claim that her current husband was paid to marry her. Karen Sypher says in Friday’s edition of the New York Post that her marriage to Tim Sypher — Pitino’s equipment manager — was all part of an elaborate plot Pitino used to keep the incident private.

NBA

Nuggets re-sign Carter

Denver — The Denver Nuggets, who lost Dahntay Jones and Linas Kleiza to free agency, have fulfilled one of coach George Karl’s offseason wishes with the re-signing of backup point guard Anthony Carter.

AUTO RACING

Vickers wins Michigan pole

Brooklyn, Mich. — Brian Vickers turned a lap of 187.242 mph on Friday, winning pole position for Sunday’s NASCAR Sprint Cup race at Michigan International Speedway. It’s the sixth pole of the season for Vickers and a continuation of his recent dominant performances in qualifying at the two-mile Michigan track. Vickers has won the pole for three straight Michigan races, most recently in June.

June Michigan race winner Mark Martin qualified second, followed by Juan Pablo Montoya, Jimmie Johnson and Martin Truex Jr.

OLYMPICS

Phelps’ license invalid

Baltimore — Olympic gold medalist Michael Phelps was driving with an invalid, out-of-state license and told police he drank a beer about an hour and 15 minutes before he was involved in an accident, Baltimore police said Friday. The accident Thursday night was not Phelps’ fault and was caused by another driver who ran a red light, police said.

TENNIS

Tsonga ousts Federer

Montreal — Jo-Wilfried Tsonga upset Roger Federer in the Rogers Cup on Friday, making a dramatic comeback to beat the world’s top-ranked player. 7-6 (5), 1-6, 7-6 (3). Federer led 5-1 in the third set before the Frenchman broke his serve twice.