BOSTON (AP) _ In his first three at-bats, Frank Thomas hit solo home runs. In his final at-bat, he looked overmatched.

Thomas became the White Sox career home run leader, but the Boston Red Sox beat Chicago 9-8 Sunday on Troy O'Leary's single with two outs in the ninth inning.

Thomas, who increased his season homer total to 35, struck out swinging against Heathcliff Slocumb wth runners on first and second to end the eighth inning with the score 8-all.

``The three homers were nice because I've never done it in my career,'' said Thomas, ``but this was a tough loss.''

The White Sox dropped 2 1/2 games behind Baltimore, which defeated Detroit 16-6, in the wild-card chase. Boston remained six games behind the Orioles.

Thomas hit solo home runs in the first, third and fifth innings against Tim Wakefield. His first drive was his 215th for the White Sox, breaking a tie with Carlton Fisk for the team lead.

Thomas, with a chance to tie the major league record of four homers in a game, drew an intentional walk in the seventh from Vaughn Eshelman and then struck out against Slocumb.

``Slocumb's a guy I haven't had much success against since Double-A,'' Thomas said. ``I gave it what I had. I kept my head on the ball. I tip my hat to him, especially on a day I felt I could hit anything.''

Thomas is now 0-for-5 in his career with five strikeouts against Slocumb.

``Hey, he had his day,'' said Slocumb. ``It just didn't seem like he looked like the same hitter (as his first three at-bats). He didn't look as confident.''

The Red Sox took two of three in the weekend series between the wild-card hopefuls.

``I knew if (Thomas) came up in the eighth or ninth that I was going to have Slocumb in there,'' said Boston manager Kevin Kennedy. ``It's not often you have your closer in in a tie game, but with the magnitude of the situation I was going to have him.''

The crowd booed Eshelman as he walked Thomas with one out and a runner on second in the seventh inning.

Mark Whiten was the last player to hit four homers in a game, doing it for St. Louis in 1993. The last AL player to do it was Rocky Colavito for Cleveland in 1959. The feat has been accomplished 10 times overall.

Thomas hit three homers in a game for the first time, and has 35 home runs this season. It was the 10th time a White Sox player hit three in a game, and first since Tim Raines at Boston on April 18, 1994.

Mo Vaughn and John Valentin each hit two home runs for Boston. Robin Ventura and Danny Tartabull also connected for the White Sox.

The nine home runs in the game tied an AL high this season, and was one short of the major league mark this year set by Colorado and Los Angeles on June 30.

White Sox reliever Roberto Hernandez (6-4) retired the first two batters in the ninth. But Mike Greenwell and Valentin singled, and O'Leary followed with a single up the middle that scored pinch-runner Lee Tinsley.

O'Leary was 5-for-35 in September prior to the game-winning hit. Slocumb (4-5) got the victory.

Valentin's second homer of the game, a two-run shot off Bill Simas in the seventh, tied it at 8.

Vaughn has 41 home runs this season. He became the first Red Sox player to reach the 40-mark since Tony Amras hit 43 in 1984.

Notes: White Sox starter Kevin Tapani entered the game 9-0 with a 2.98 ERA in his career against Boston. ... The first five Chicago hits were all solo homers. ... Reggie Jefferson of the Red Sox extended his hitting streak to a career-high 16 games. ... Tony Phillips and Ray Durham, both switch-hitters, batted right-handed against right-handed knuckleballer Wakefield. Greg Norton, also a switch-hitter, batted lefty. ... Thomas recorded his 11th career multi-homer game.