HOUSTON – Steve Trachsel earned his first win with the Cubs in eight years and Chicago hit four home runs to regain the NL Central lead by beating the Houston Astros 6-2 on Thursday night.

Alfonso Soriano, Aramis Ramirez, Daryle Ward and Cliff Floyd all homered for Chicago, which moved a half-game ahead of idle Milwaukee in the division race. The Cubs open a four-game series at third-place St. Louis on Friday night.

Trachsel (1-2) gave up two solo homers and seven hits in five innings to record his first victory since the Cubs acquired him from Baltimore in a waiver deal on Aug. 31.

The 36-year-old right-hander pitched for the Cubs from 1993-99, and his last win with them came on Oct. 3, 1999. The 2,906-day gap between victories is the third-longest in team history.

Kerry Wood and two other relievers combined for four scoreless innings of one-hit ball.

Carlos Lee and Mark Loretta homered for the Astros, who have dropped 10 of 15 games since Cecil Cooper replaced Phil Garner as manager on Aug. 27. Woody Williams (8-15) gave up four homers for the first time this season and lost his fourth straight start.

The Cubs staked Trachsel to a 4-0 lead in the first inning.

Soriano hit Williams’ second pitch off the brick facade in left field, his 40th career leadoff homer. Soriano has eight leadoff home runs this season, tying the Cubs record set by Rick Monday in 1976.

Mike Fontenot followed with a single and Floyd walked before Ramirez hit a three-run shot to left. Ramirez has 23 home runs this season and five this month.

Chicago’s defense helped Trachsel avoid early trouble.

Luke Scott tripled with one out in the Astros’ second at-bat in their half of the inning, his second triple of the series. Loretta walked before Eric Munson grounded into a double play. The Astros also put two on with one out in the third inning, but Chicago escaped with another double play.

Lee led off the fourth inning with his 28th homer and the first for him since Sept. 1. With two outs in the Astros’ half of the inning, Loretta homered just inside the foul pole in left.

Williams retired 11 consecutive batters after the shaky start. Ward ended the streak with a two-out, solo homer in the fifth that stretched Chicago’s lead to 5-2.

Left-hander Scott Eyre relieved Trachsel in the sixth and the Cubs ended another inning with a double play. Eyre has a 1.02 ERA since the All-Star break.

Floyd led off the seventh with a homer into the upper deck in right field. The only other time the Cubs hit four homers in a game this season was June 8 in a 9-1 victory against the Atlanta Braves.

Chicago’s bullpen did the rest. Wood pitched a perfect seventh and Carlos Marmol shut out the Astros in both the eighth and ninth innings to cap off the victory.