Yadier Molina has been guiding the St. Louis Cardinals' pitching staff all season. The All-Star catcher played a big role in this one, helping Michael Wacha get his 14th win.

"Everyone knows about what he does behind the plate," Wacha said after a 4-2 victory over the Pittsburgh Pirates on Wednesday night. "He was all over the place, big knocks, stealing bags — it was a lot of fun to watch."

Molina tripled in the go-ahead run in the sixth inning when right fielder Gregory Polanco missed an attempted shoe-top catch. He also threw out Polanco attempting to steal from his knees in the first and stole his second base of the season after doubling in the eighth when the Cardinals won an appeal to have the call overturned.

"We love his aggressiveness," manager Mike Matheny said. "Yadi's coming out of the box and he sees what happens and he's thinking three.

"He's opportunistic on the bases. He's got guts."

As for Polanco, there was a spanking to be absorbed.

"You'd have liked to be able to keep that ball in front of you," manager Clint Hurdle said. "At that point in time of game, runner on first in that situation you're going to be first and second. "

The anticipated marquee pitching matchup between Wacha (14-4) and Gerrit Cole (14-6) didn't live up to expectations, as both were gone by the seventh inning. Seattle's Felix Hernandez also has 14 wins.

"I felt really good out there," Wacha said. "I just wanted to keep pumping strikes."

"The fastball location was sub-par," Cole said. "It hasn't been the easiest few starts."

St. Louis gave up an easy run, too, when center fielder Randal Grichuk badly misplayed an attempted diving catch on Andrew McCutchen's RBI triple that tied it at 2 in the fifth. Grichuk landed early and bounced as the ball rolled past him to the wall.

Kevin Siegrist worked two perfect innings and Trevor Rosenthal finished for his 35th save in 37 chances.

The Cardinals lead the second-place Pirates by seven games and will attempt to complete a three-game sweep on Thursday night. St. Louis improved to a season-best 33 games above .500 at 73-40.

McCutchen hit his 18th homer and Polanco had three hits for the second straight game for the Pirates, who are 0-5 in St. Louis and 5-2 against the Cardinals at home. The first four losses at Busch Stadium were all by one run.

Wacha scattered nine hits and three walks in six innings, allowing two runs. Pittsburgh left the bases loaded in the fourth and stranded two in the fifth and sixth.

Cole gave up three earned runs in 5 1/3 innings and is 0-2 in three starts this month while totaling 16 1/3 innings. A throwing error by second baseman Neil Walker on a potential double-play ball by Jason Heyward in the third handcuffed first baseman Pedro Alvarez on a short hop and led to the Cardinals' first two runs.