Updated

If the Pirates are going to move back into first place in the NL Central Sunday, Charlie Morton will likely have to accomplish something he hasn't done since early in the 2011 season - beat the Cardinals.

The Pirates, who enter this finale of a three-game series a half-game behind St. Louis for first place, are in danger of being swept and have lost their last eight series finales.

Morton, who has won each of his last four road decisions, is 4-0 over his last six overall appearances and hasn't lost since Aug. 1, when the Cardinals dominated the Bucs in a 13-0 rout. He also got a no-decision in a 4-3, 14- inning walkoff loss at Busch Stadium on Aug. 13.

Over his career, Morton is 2-8 with a 6.00 ERA in 13 starts against St. Louis. He has gone 0-5 in his last seven starts since winning a 4-3 decision over Kyle Lohse at Busch Stadium on April 4, 2011.

Rookie right-hander Michael Wacha takes the mound for the Cardinals. Wacha, who will make his sixth career start and 12th appearance in the majors, faced the Pirates on Aug. 14 and pitched two scoreless innings. He struck out four of his six batters faced.

Wacha threw six scoreless innings on Tuesday against the Reds. He hasn't given up a run over his last four appearances and not since Aug. 19 at Milwaukee.

On Saturday, Adam Wainwright got back on track by firing seven scoreless innings, with the gem sending the Cardinals back into first place with a 5-0 win. Wainwright passed Dizzy Dean for second on the Cardinals' all-time strikeout list with 1,096. . Battered for 15 runs over eight innings during consecutive losses to Cincinnati in his last two starts, Wainwright (16-9) reclaimed his All-Star form and joined Colorado's Jorge De La Rosa and Washington's Jordan Zimmermann for the NL lead in wins. The ace righty yielded just two hits and a pair of walks, struck out eight, and set down the final 11 men he faced.

"I didn't throw a bullpen session between the last start and this one because I didn't want to go out and practice bad mechanics," Wainwright said. "I didn't have a plan yet so I didn't want to go out and work on something that was counterproductive."

David Freese supplied the offense for the Cardinals with a solo homer and two RBI, while Yadier Molina doubled twice and scored a pair of runs.

Andrew McCutchen had two of Pittsburgh's three hits as the Pirates were handed a third straight loss that includes a 12-8 setback in Friday's opener.

"It's just a sense of not panicking," McCutchen said of the standings. "We have a lot of ball left, anything can happen."

Jeff Locke (9-5), making his first start since Aug. 27, worked five innings for the Pirates and permitted three runs -- two earned -- while walking four.

Pittsburgh is 10-8 against the Cardinals this season.