Wainwright (1-0), who got the last out against Detroit to help St. Louis win the title, also had an RBI double and scored on Chris Duncan's two-run homer in the third inning to help the Cardinals avoid their first 0-4 start since 1997.
Duncan also had an RBI double in the eighth as St. Louis snapped a five-game losing streak to the Astros.
Pinch-hitter Orlando Palmeiro hit an RBI single off Jason Isringhausen with two outs in the ninth, but Jason Lane flied out and Isringhausen earned his first save of the season and 250th of his career.
Carlos Lee had a sacrifice fly to drive home the first run for the Astros, who are off to their worst start since they opened 0-4 in 1990.
Wandy Rodriguez (0-1) gave up only four hits and struck out five in seven innings, but still lost his fifth straight decision.
CINCINNATI - Jeff Conine hit a three-run homer and tripled, leading the Reds to a victory that ended Pittsburgh's unbeaten streak.
The 40-year-old outfielder, acquired in a December trade to platoon at first base, led the Reds to a win for the second day in a row. Conine also had a game-tying, pinch-hit single and scored the go-ahead run against the Cubs on Thursday.
He homered off Pittsburgh's Paul Maholm (0-1) in the third inning for a 4-1 lead on Friday. He also beat out a triple to the wall in center field in the sixth.
The Pirates opened the season 3-0 for the first time since 2003, but couldn't keep the winning streak going against right-hander Matt Belisle (1-0), who retired 14 in a row over the middle innings.
WASHINGTON - Micah Owings allowed one hit in five shutout innings in his big league debut, and Chris Young homered and drove in four runs for Arizona.
Owings (1-0) struck out six, including Ryan Zimmerman on three pitches with the bases loaded in the fifth. The victory stretched Owings' undefeated streak to 20 starts and made him 13-0 in decisions dating to May 23, 2006: That includes 2-0 at Double-A Tennessee and 10-0 at Triple-A Tucson last season.
Jerome Williams (0-1) went six innings - the first Nationals starter to pitch more than five - and allowed five runs, four earned.
Ryan Church homered with two outs in the ninth for Washington's only run.
MILWAUKEE - Rich Hill retired his first 15 batters and allowed one hit in seven innings for Chicago.
Hill's run at a perfect game and a shutout ended in the sixth when Corey Hart led off and hit a fastball deep into the Brewers' bullpen to cut Chicago's lead to 6-1.
Hill (1-0) got all the run support he needed before he stepped on the mound as the Cubs scored six times in the first inning, capped by Mark DeRosa's two-run homer.
Dave Bush (0-1), who won nine of his 12 games last season at Miller Park, allowed six runs, eight hits and struck out seven in six innings.
MIAMI - Pat Burrell homered and drove in four runs, Jamie Moyer pitched 6 2-3 innings and Philadelphia earned its first victory after three consecutive losses.
Burrell hit a three-run homer and an RBI single, and Jimmy Rollins hit a two-run homer for the Phillies, who scored four unearned runs thanks to two Florida errors.
The 44-year-old Moyer (1-0) allowed seven hits and two runs before departing after 93 pitches.
Hanley Ramirez hit a solo homer for Florida, which had its home opener and drew 40,397 - its largest crowd at home since the 2005 opener.
Florida's Sergio Mitre (0-1) pitched five innings and allowed five runs, only one earned. He missed most of last season with a shoulder injury.
SAN DIEGO - Greg Maddux was mediocre in his Padres debut, getting chased by Matt Holliday's two-run homer into San Diego's bullpen that helped carry Colorado to the win.
Kazuo Matsui had three hits, two stolen bases, an RBI and a run scored for the Rockies, who won their third straight following an opening-day loss to Arizona.
Khalil Greene hit a two-run homer off Brian Fuentes with no outs after Mike Cameron was hit with a pitch to lead off the inning. Fuentes settled down and got three outs to seal his first save in as many chances.
Pitching eight days before his 41st birthday, Maddux (0-1) allowed four runs and five hits in 5 1-3 innings. Noted for his control throughout his brilliant career, the 333-game winner also hit a batter and allowed a run to score on a wild pitch. He struck out four and walked one.
Jason Hirsh (1-0) made his Rockies debut a memorable one, striking out a career-high eight while walking none and holding San Diego to one run in 6 2-3 innings. Hirsh allowed five hits, including Terrmel Sledge's homer in the fifth.