Jose-Maria Olazabal continued his record-breaking assault on one of America's most difficult courses and threatened to run away from the winners-only field in the World Series of Golf in Akron, Ohio.

The 24-year-old Spaniard added a three-under-par 67 to his opening 61 and reached the tournament halfway point yesterday with a 128 total and a nine-stroke lead at Firestone Country Club.

The huge 36-hole lead may or may not be the largest in PGA Tour history. "We simply don't know," said Tom Place, the tour's director of information.

"I know everyone else is saying it is now mine to lose," said Olazabal, a bright young star on the European circuit but an infrequent competitor in this country. "With a nine-shot lead, I should win. But I could lose. I've played for a while now and I know anything can happen in this game.

"Maybe I shoot three over par tomorrow and somebody shoots five under and it's very close."

His closest pursuers, U.S. Open champion Hale Irwin and Larry Mize, agreed: Olazabal must back away for anyone else to have a chance.

"Mr. Olazabal has to come back to us," Irwin said. "It's a fairly competitive tournament except for one man. I just can't see him playing four rounds like this, but maybe he can."

The best 72-hole score is 257, one more than Olazabal's current pace.

"It's going to be tough to catch Jose with such a big lead," Mize said. "But it can be done. I'm not throwing in the towel yet."

Olazabal's total is 12 under par and -- by three strokes -- the record for two rounds at 7,148-yard, par-70 Firestone. The 36-hole score also is -- by two strokes -- the best of any in the 34 PGA Tour events played this season. It's two strokes off the tour's all-time record for the first two rounds.

Irwin and Mize shared second in the 47-man international field at 137, Irwin with a solid, three-under-par 67 and Mize with a scrambling 71.

Payne Stewart, Lanny Wadkins and Donnie Hammond were at 138. Wadkins shot 68 and Stewart 73. Hammond improved from a tie for 33rd to a tie for fourth with a bogey-free 65, best round of the day.

Olazabal, winner of an English tournament and the Irish Open earlier this season, had a four-stroke advantage when he started and wasted no time expanding it. He dropped an 18-foot birdie putt on the first hole, reached the par-5 second with a 3-wood second shot and two-putted for birdie.

A 6-iron shot at the 12th set up a three-foot birdie putt that gave him a seven-stroke lead. He went to eight in front with a 22-foot putt on the 14th and dropped another six-footer on the 17th.

Northgate LPGA Classic: Barb Bunkowsky, whose only LPGA victory came six years ago, matched her career low round with a seven-under-par 65 to lead by one stroke after the first round in Brooklyn Park, Minn. She had one bogey and eight birdies.

Beth Daniel, winner of two of her last three tournaments, shot 66 to share second with Cindy Rarick and Chris Johnson. Of the 120 starters, 26 finished under par on the par-72, 6,149-yard Edinburgh USA course.

Chattanooga Classic: Peter Persons holed a 60-foot chip shot for an eagle-3 on the 17th hole. His second straight round of six-under-par 64 for 128 and two shots ahead of Mitch Adcock (66) and Steve Lowery (68) at the 6,641-yard, par-70 Valleybrook Golf and Country Club course. Lowery, who had a 62 in the first round, made the turn at one-over, but rallied with three birdies on the back nine for 68.

U.S. Amateur: Two-time NCAA champion Phil Mickelson advanced to the quarterfinals, finally overtaking Mike Swingle for a 1-up victory with a birdie on the par-5 17th hole -- the same hole that eliminated Jay Sigel earlier in the day.

Mickelson, 20, of Arizona State, who paced qualifying for this match-play tournament, is the lone favorite still in the field. Defending champion Chris Patton lost Thursday, and Sigel, winner in 1982 and 1983, lost to former tour pro Mike Brannan in the second round.

Bob May of La Habra, Calif., went 22 holes to get by Bill Edwards of Moultrie, Ga., 1-up, to advance.