Miller (8-4), who had to wait out a rain delay of 1 hour, 59 minutes to start the game, left due to cramping in his right leg. He allowed just two hits and struck out five in the shortest start of his career. His previous shortest stint was 5 1-3 innings at Los Angeles on May 26.
Kevin Siegrist and Seth Maness followed Miller and combined for two shutout innings before Trevor Rosenthal allowed a run in the eighth on a broken bat single by Nate Schierholtz. Edward Munica gave up a homer to Darwin Barney with two outs in the ninth, but still earned his 20th save in 20 opportunities.
Molina also had a single in four at-bats to raise his average to a National League leading .355. Shane Robinson and Allen Craig added sacrifice flies for the Cardinals, who moved back to a major league best 20 games over .500 (45-25).
Chicago fell to 8-22 against the National League Central, the lowest winning percentage by any team in its own division (.266). The Cubs are 5-23 when they score three runs or less, including Travis Wood's last three starts. Wood (5-6) was again a hard-luck loser, as he gave up four runs on seven hits. He has dropped three straight games despite having a 2.70 ERA in those contests.
The Cardinals took a 2-0 lead in the fourth. Carlos Beltran and Matt Holliday started the inning with singles, and Beltran then went to third on Craig's long fly out to right. Molina then drove both Beltran and Holiday home with a double to the gap in right center.
St. Louis began the seventh the same way, with Molina and David Freese getting singles. Molina would score on a throwing error by first baseman Anthony Rizzo and Freese came home on Robinson's sacrifice fly.
Craig's sacrifice fly in the eighth gave the Cardinals a 5-1 lead.
NOTES: The Cardinals' Adam Wainwright (10-3) will try to become the Major League's first 11-game winner when he opposes Jeff Samardzija (3-7) in the second game of the series Tuesday. ... Chicago manager Dale Sveum was ejected with one in the seventh inning after arguing with home plate umpire D.J. Reyburn over whether Molina had eluded Wood's tag. ... St. Louis is 17-7 in the first game of a series. ... Schierholtz has a nine-game hitting streak, equaling his career best.
Link to box score: St. Louis 5, Chicago 2
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