ST. LOUIS -- Yadier Molina continued the best season of his major league career Wednesday night at the Chicago Cubs' expense.
The St. Louis catcher snapped a 1-1 tie in the bottom of the sixth inning with a two-run homer and the Cardinals went on from there to a 4-1 win at Busch Stadium.
It was the fifth homer of 2013 for Molina, who rode a 1-2 fastball from Edwin Jackson (3-9) over the left field wall with Allen Craig at first. Molina, who leads the National League in batting at .365, is 9-for-15 with three homers in his career against Jackson.
Pete Kozma added an RBI single later in the sixth off reliever Carlos Villanueva as St. Louis (46-26) tied its season high at 20 games over .500.
Jake Westbrook (3-2) went seven innings for his first win since May 2, allowing just two singles and an unearned run. He walked three and struck out two, picking up 15 outs on ground balls.
Edward Mujica worked a 1-2-3 ninth on just eight pitches for his 21st save in as many chances. St. Louis jumped on top in the bottom of the first against Edwin Jackson when Allen Craig singled Matt Carpenter home from second with one out. It was the 53rd RBI for Craig.
Chicago tied it in the second with some awful defense from the Cardinals, who entered the night with only 25 errors in 71 games. Carpenter turned an almost certain 4-6-3 double play into a two-base throwing error by flipping the throw several feet over Kozma's head.
Darwin Barney's bases-loaded sacrifice fly to short center field brought Anthony Rizzo home to make it 1-1. Jon Jay's throw beat Rizzo by about five feet, but Rizzo kicked the ball out of Molina's glove for a second error that allowed the other runners to move up.
That was all the Cubs (29-41) got off Jake Westbrook through five innings as the veteran righthander allowed just two hits and picked up nine outs off grounders. Jackson steadied after the first, allowing just two hits in the next four innings.
NOTES: Chicago manager Dale Sveum said the team could make a roster move by Friday to add a position player and send a reliever down to the minors. The Cubs' active roster currently has just four reserves and eight relievers. ... St. Louis Wednesday announced the signing of its top first round draft pick, lefthanded pitcher Marco Gonzales of Gonzaga University. Gonzales threw a bullpen session before Wednesday night's game and will start his pro career in the Gulf Coast League. ... Tuesday night's loss was the Cardinals' eighth in June. They had just seven in May.