St. Louis and Pittsburgh share the division lead once again. The Pirates topped the Cubs 2-1.
The Cardinals mustered only three hits, including Matt Carpenter's league-leading 50th double in the eighth. He later scored on a wild pitch by Charlie Furbush.
Franklin Gutierrez hit a two-run double in the fifth inning that ended St. Louis rookie Michael Wacha's scoreless streak at 23 2-3 innings. Kendrys Morales hit his 22nd homer in eighth off Tyler Lyons to make it 3-0.
The St. Louis hitters have been struggling all week, and they never got going at all against the 24-year-old Paxton (2-0), who limited them to a pair of singles.
The first was by Wacha (3-1) in the third when Paxton came off the bag to field a tapper and then slipped and fell, losing his grip.
The Cardinals managed three hits in seven scoreless innings to start the weekend series against the Mariners before winning 2-1 in 10 innings. They broke up no-hit bids in the sixth against Wily Peralta and Marco Estrada, winning both games while taking two of three from the Brewers.
Paxton struck out five and walked two. He won his major league debut a week ago against Tampa Bay, allowing an earned run in six innings.
Danny Farquhar finished for his 14th save in 16 chances.
Wacha struck out five in his seventh career start but also walked four in five innings.
Mariners pitchers were 0 for 20 with 13 strikeouts at the plate this year before Wacha walked Paxton on four pitches in the fifth to put runners on first and second with none out, setting up Gutierrez's double.
Seattle leadoff man Brad Miller was removed with a mild left hamstring strain after running out a sacrifice bunt in the fifth. Replacement Carlos Triunfel had a sacrifice fly in the ninth off Fernando Salas.
NOTES: Yadier Molina, who threw out two runners attempting to steal in the same inning Friday, was the first Cardinals C to do that since manager Mike Matheny on May 1, 2001, at Florida. Matheny said he didn't remember the occasion, but added, ''You don't normally get that many opportunities unless you're stinking, or else your pitcher's just giving you no chance.''
Link to box score: Seatte 4 at St. Louis 1
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