Updated

Rookie Michael Wacha tossed seven scoreless innings and singled home a pair during a four-run fifth, as the St. Louis Cardinals wrapped up a convincing three-game sweep of the Pittsburgh Pirates with Sunday's 9-2 win at Busch Stadium.

Matt Carpenter, Jon Jay and David Freese each had two hits and one RBI for the NL Central-leading Cardinals, who are now 1 1/2 games up on the second-place Pirates and Cincinnati Reds in the division standings. Wacha (3-0) scattered two hits and walked two during his impressive outing.

"That was our last opportunity to play those guys," Carpenter said. "We needed to come out and have a big series, and I don't think you can have a bigger one than getting the sweep like we did."

Pittsburgh lost starter Charlie Morton (7-4) to injury in the second inning. Morton had struggled on the mound before being removed with discomfort in his left foot, having been tagged for five runs and six hits while recording just five outs.

The Pirates have lost four games in a row, tying a season high, and remain one victory shy of securing their first winning season since 1992.

"We weren't sharp in any particular area of the game all weekend," Pirates manager Clint Hurdle said.

Morton found himself in immediate trouble as singles by Carpenter and Jay and a walk to Matt Holliday loaded the bases with no outs. Carpenter scored on Carlos Beltran's sacrifice fly and a fielder's choice by Yadier Molina plated Jay.

The Pittsburgh right-hander gave up doubles to three of the first four batters in the second, with Carpenter and Jay each driving in a run. Jay eventually scored on a wild pitch that was also ball four to Beltran. Morton was replaced by Stolmy Pimentel following the two-out walk.

Pimentel allowed an RBI single to Freese in the fifth before Vin Mazzaro took over on the mound. Mazzaro gave up three straight hits, with Wacha plating Freese and Matt Adams. Holliday added a run-scoring single off Jared Hughes.

Garrett Jones spoiled St. Louis' shutout bid with an RBI double in the ninth and Gaby Sanchez scored Jones with a fly to right.

Game Notes

Morton, who was 4-0 with a 1.74 ERA in his previous six starts, will undergo treatment and further evaluation in the next few days. He is now 0-6 in his last eight starts against the Cardinals ... St. Louis outhit the Pirates, 12-4 ... The Cardinals were 6-for-12 with runners in scoring position.