Davey Lopes, playing his first game for Houston, singled home Dickie Thon with two out in the 11th inning to give the Astros a 4-3 victory -- their sixth straight -- over the Montreal Expos yesterday in Houston.

Montreal reliever Tim Burke (7-3), who walked the bases loaded in the 10th but did not allow a run, walked Thon to open the 11th. Thon was sacrificed to second and, one out later, Lopes singled to left on Burke's first pitch.

Mets 3, Reds 2: Kevin Mitchell's two-run eighth-inning homer gave New York the victory and a second three-game series sweep in Cincinnati this season.

Mitchell's seventh homer came off Ron Robinson (7-1), who gave up a single to Gary Carter to begin the eighth. Roger McDowell recorded his ninth save in relief of Ron Darling (10-3), who is the Mets' fourth 10-game winner.

Cardinals 4, Giants 3: Danny Cox (4-8) allowed six hits over eight innings and Andy Van Slyke drove in two runs to lead visiting St. Louis.

The Cardinals broke a 1-1 tie with a three-run sixth on Ozzie Smith's RBI single, Van Slyke's triple and Terry Pendleton's sacrifice fly off Mike LaCoss (9-5).

Dodgers 6, Pirates 5: Ken Landreaux ended a zero-for-14 slump with a two-run homer and Mike Scioscia drove in two runs as Los Angeles won in Pittsburgh.

Landreaux's third-inning homer broke a 2-2 tie and gave Rick Reuschel (5-12) his eighth loss in nine decisions. Orel Hershiser (9-7) was the winner.

Phillies 4, Braves 2: Juan Samuel and Von Hayes homered and rookie Bruce Ruffin (3-1) pitched a six-hitter for visiting Philadelphia. Atlanta has lost 14 of its last 16.

Padres 7, Cubs 5: In Chicago, Marvel Wynne's eighth-inning double broke a 5-5 tie as San Diego ended a five-game losing streak.

Steve Garvey singled off Ray Fontenot (3-5) to begin the eighth and was sacrificed to second. Wynne followed with his seventh game-winning RBI.