Three weeks ago, Houston Manager Hal Lanier rewarded Mark Bailey with a vote of confidence. Yesterday, Bailey rewarded the Astros with a game-winning RBI.

The 24-year-old catcher, batting .172, snapped a 1-1 tie with a run-scoring single off Fernando Valenzuela in the sixth inning, helping Mike Scott to a 3-2 triumph over the Dodgers in Los Angeles.

"Hal called me into his office and said, 'I'm going to stick by you through the good times and bad,' " Bailey recalled. "It's been mostly bad times, though."

But not in the sixth inning yesterday.

Glenn Davis beat out an infield hit and Phil Garner walked. Bailey then singled to short center for a 2-1 Astros lead.

Scott (6-4) pitched a five-hitter, walking two and striking out nine over 8 2/3 innings. After giving up Franklin Stubbs' 10th homer of the year to lead off the ninth, Scott got two outs before Dave Smith finished up for his league-leading 15th save.

Scott leads the NL with 115 strikeouts while Valenzuela (8-4) had nine over seven innings for 96 on the season. Scott also contributed a run-scoring, two-out single.

Billy Hatcher was four for five for the Astros, including his first homer this season.

*Mets 4, Pirates 3: Kevin Mitchell drove in three runs with a homer and a single, leading New York to victory in Pittsburgh.

Mets starter Sid Fernandez (6-2) got into trouble by walking six, but was bailed out by Roger McDowell, who worked 2 1/3 scoreless innings, and Jesse Orosco, who got the last two outs for his 10th save.

Mitchell's home run, his third of the season, came in the fourth off loser Larry McWilliams (1-4). With Tim Teufel on base on an error by third baseman Jim Morrison, Mitchell hit a fly ball that the wind carried over the left field wall.

*Reds 7-1, Giants 3-3: Consecutive suicide squeeze bunts by Mike Woodard and Robby Thompson broke a 1-1 eighth-inning tie in the second game of a doubleheader in San Francisco and gave the Giants a split with Cincinnati.

Mike Aldrete led off the Giants eighth with a single off reliever Ted Power (3-4). Chris Brown walked and Jeffrey Leonard sacrificed. After Chili Davis was walked intentionally, pinch hitter Woodard bunted to the right side to score Aldrete. Thompson followed with a squeeze bunt to the pitcher that scored pinch runner Luis Quinones.

In the first game, Dave Parker drove in three runs with a homer and a double and John Denny (4-5) struck out a season-high 10 for Cincinnati. Pete Rose's two-run triple keyed a three-run ninth inning for the Reds in that game.

*Cubs 14, Cardinals 2: Keith Moreland hit a three-run homer as Chicago scored nine runs in the sixth inning for the victory in St. Louis.

Chicago's sixth inning, the biggest in the NL this year, helped Steve Trout (3-3) win a seven-inning seven hitter. The Cubs, who totaled 20 hits, had seven straight and sent 13 batters to the plate in the sixth against rookie Greg Mathews (1-1) and two relievers. Moreland started it off with a walk and capped it with his sixth homer, making the score 12-0. The other big hits of the inning were a triple by Leon Durham and a two-run single by Ryne Sandberg.

"We need to start getting some clutch hits and starting putting some hits together," Moreland said of the Cubs, 14 1/2 games out of first. "I guess it's just about what you could say of any team in our position."

*Padres 4, Braves 1: Mark Thurmond threw a three-hitter and drove in all four San Diego runs with a single and a double in beating visiting Atlanta. Twice, the Braves walked Garry Templeton with two outs to pitch to Thurmond and each time he followed with a two-run hit. "Like they say, it's a game of inches," Thurmond said. "Three inches probably separated them his hits from being two outs. When you're a pitcher, you notice those things."

Thurmond (3-4) retired the first 10 batters, then Rafael Ramirez hit a solo homer in the fourth.

*Expos 12, Phillies 0: Rookie Floyd Youmans allowed only one hit, an infield single in the fourth by Glenn Wilson, and hit a two-run homer in the victory over Philadelphia in Montreal. Under orders from Manager Buck Rodgers and pitching coach Larry Bearnarth, Youmans abandoned his curveball for the game and threw fastballs and change-ups.

Tim Raines hit a grand slam, Hubie Brooks had a two-run homer in the first and Youmans' homer came in the second. The shutout, complete game and the homer all were career firsts for Youmans (5-5), who struck out eight and walked seven.