ST. LOUIS -- A rare Yadier Molina triple, aided by the last of a spate of defensive misplays by the Pittsburgh Pirates, enabled the St. Louis Cardinals to clinch a series win against their closest National League Central pursuer.

Molina's one-out run-scoring three-bagger in the bottom of the sixth inning Wednesday night snapped a tie and helped St. Louis bag a 4-2 victory.

Right fielder Gregory Polanco tried for an ankle-high catch on Molina's liner but missed as the ball rolled past him and to the wall, scoring center fielder Randal Grichuk.

It was just the fifth triple of Molina's 12-year big league career, but his second in three weeks.

Left fielder Stephen Piscotty singled up the middle to score Molina and knock out starter Gerrit Cole (14-6), who was charged with four runs off seven hits and two walks in 5 1/3 innings. Cole fanned six.

Michael Wacha (14-4) earned the win with six innings, working around multiple jams during the last three innings. Wacha yielded nine hits and two runs, walking three and whiffing seven.

Trevor Rosenthal took care of the ninth for his 35th save as the Cardinals (73-40) pushed Pittsburgh (65-46) seven games back in the division, beating it for the 18th time in their last 21 meetings at Busch Stadium.

St. Louis broke the scoring seal in the bottom of the third with help from Pittsburgh's infield defense.

A fielder's-choice grounder by right fielder Jason Heyward scored Wacha for the first run. Second baseman Kolten Wong scampered home from second when second baseman Neil Walker's throw to first bounced away from first baseman Pedro Alvarez.

Center fielder Andrew McCutchen got the Pirates on the board in the fourth with a leadoff homer to right, his 18th home run of the year.

An inning later, McCutchen tied it when his one-out liner to center bounced past a falling Grichuk for a triple that plated Polanco.

NOTES: Pittsburgh 3B Josh Harrison (left thumb) and SS Jordy Mercer (left knee) went 1-for-4 and 0-for-3, respectively, in the start of their rehab assignments Tuesday night at Triple-A Indianapolis. ... St. Louis RHP Trevor Rosenthal's save Tuesday night was the sixth of his career in which he struck out the side in the ninth, the most by any closer in team history. ... Pirates RHP Rob Scahill (right forearm) pitched three scoreless innings on a rehab assignment for Double-A Altoona on Tuesday night, throwing 21 of his 34 pitches for strikes.