The right-hander might not need his best stuff given how the Colorado Rockies are struggling at the plate.
Wainwright and the Cardinals go for their ninth win in 10 games Saturday when this series continues at Busch Stadium.
Looking to rebound from his first defeat of the season, a 2-1 loss to Cincinnati on April 29 that ended his run of four consecutive winning starts, Wainwright (4-2, 2.72 ERA) yielded a season-high five runs and 11 hits while not receiving a decision in last Saturday's 7-6 win at Milwaukee.
He also gave up his first two homers of the season.
"It wouldn't have been any fun for the rest of the team if I'd gone out and dominated and thrown a shutout," Wainwright told the Cardinals' official website.
It wouldn't be a surprise if Wainwright, 3-1 with a 1.64 ERA in five starts against Colorado, flirted with one Saturday.
The Rockies (19-16) have a .103 batting average with three runs during a three-game skid. Colorado had one hit in Friday's 3-0 series-opening loss, a leadoff bloop single by Eric Young. Rookie Shelby Miller set down the next 27 Rockies, including 13 by strikeout.
"I think this is one of those nights where we ran into a pitcher that had everything working," said manager Walt Weiss, whose team has dropped 12 of 18 since a season-best 8-0 run.
Colorado, loser of 14 of 18 to St. Louis, will try to avoid its longest skid of the season with Jhoulys Chacin (3-1, 2.56) on the hill.
The right-hander makes his second appearance following a stint on the disabled list with a lower back strain. In his first start since April 19, Chacin allowed season highs of six runs and eight hits over seven innings in Sunday's 8-3 home loss to Tampa Bay.
"Overall I felt good," said Chacin, who gave up four runs over six innings to lose his only other start against St. Louis (22-12). "... There were a couple of bloopers and some bad luck in the sixth inning. But you just want to go out and get the outs."
That could be tough with the Cardinals getting production throughout their lineup. Carlos Beltran hit his team-leading ninth home run in the opener and is 13 for 36 with three homers in his last eight games.
The Rockies' lineup could get a boost if Michael Cuddyer, tied for second on the team with seven homers and a career .345 hitter against the Cardinals, returns after missing the last two games with a sore neck.
The Cardinals, who opened a season high-tying 10-game homestand Friday, have won 10 of 12 with the Rockies in town.