MILWAUKEE -- Adam Wainwright walked away with confidence after his long-awaited return to the mound in a game that counts, even if he couldn't deliver a win for the St. Louis Cardinals.

Wainwright, who missed last season because of elbow surgery, gave up four hits and three runs with a walk and six strikeouts over 5 2/3 innings in a 6-0 loss to the Milwaukee Brewers on Saturday.

It was the first regular-season start for Wainwright (0-1) since Sept. 24, 2010, a span of 563 days.

"It's just another step toward getting back to being a great big-league pitcher like I know I can be," Wainwright said.

It wasn't enough for the Cardinals. Corey Hart homered twice and Zack Greinke pitched four-hit ball for seven innings. Greinke (1-0) continued the dominant form he showed at Miller Park all last season. He didn't walk a batter and struck out seven.

Cardinals starting pitcher Adam Wainwright delivers during the first inning Saturday in Milwaukee. (JEFFREY PHELPS ~ Associated Press)

Greinke's strong outing overshadowed the long-awaited return of Wainwright, but he still impressed Cardinals manager Mike Matheny.

"He was right in that area we wanted him to be," Matheny said. "We didn't want him to go much further but wasn't alarmed by anything we saw. The one breaking ball, which was the last one he threw was up, really the only indication of any kind of fatigue at all. I thought he got better as he went. In general, I think we're going to be as smart as we can with all of them, let alone a guy just coming off Tommy John."

Rickie Weeks homered, while Aramis Ramirez and Carlos Gomez added RBI doubles for the Brewers, who rebounded after dropping Friday's opener. Ryan Braun had a pair of doubles and drew a walk after going 0 for 5 on Friday.

Hart led off the second with a monster home run, so deep that left fielder Matt Holliday didn't even move when the ball came off the bat.

Wainwright settled down until the sixth, when he allowed a leadoff single to Weeks, then committed a throwing error that allowed Nyjer Morgan to reach first on a sacrifice bunt attempt.

Brewers outfielder Ryan Braun asks for time after hitting a double against the Cardinals during the eighth inning Saturday.

Wainwright then got Braun to hit into a double play, which sent Weeks to third. Ramirez doubled off the wall in left-center field to score Weeks and give the Brewers a 2-0 lead.

Matheny lifted Wainwright in favor of Victor Marte, and Hart pounced on a pitch for a two-run homer to center and a 4-0 lead. It was the 12th multi-homer game of Hart's career.

Greinke gave up only three hits over the first five innings -- a pair of singles by David Freese, one of which was an infield hit, and a ball off the bat of Jon Jay that originally was ruled an error but later was changed to a base hit.

Things seemed to start unraveling in the sixth when Greinke gave up a one-out single to Rafael Furcal and allowed him to go to second base on a wild pitch. But Greinke struck out Carlos Beltran and got Holliday to ground out.

Greinke was unbeatable at home for the Brewers last season. He went 11-0 with a 3.13 ERA in 15 home starts during the regular season and earned a win in the playoffs.

Greinke can become a free agent at the end of the season, which makes his future a critical question for the Brewers.

Brewers general manager Doug Melvin said Friday that he and Greinke's agent, Casey Close, discussed a potential new deal.

Francisco Rodriguez pitched a scoreless eighth, and Jose Veras closed out the ninth for Milwaukee.