With ace Chris Carpenter hurt and former 20-game winner Adam Wainwright struggling, the Cardinals' rotation was in danger of falling apart.

That hasn't been the case thanks to a supporting cast led by Kyle Lohse, who goes after the first 4-0 start of his career this afternoon in the second of three straight games against the rival Milwaukee Brewers.

Carpenter has yet to pitch this season due to a right shoulder injury, while Wainwright is 0-3 with a 7.32 earned run average through four starts after missing all of last season due to Tommy John surgery.

Those elements figured to test St. Louis' pitching depth, but Lance Lynn has jumped right in and won his first four decisions in place of Carpenter, while Lohse is 3-0 for the first time since 2009. In fact, the right-hander could already be off to the first 4-0 beginning of his career if not for a blown save on April 17 versus the Reds.

Lohse bounced back from that no-decision to win at Pittsburgh on Sunday, allowing a run on six hits over seven innings with five strikeouts. He also did not walk a batter and has issued just two walks in addition to three runs through 27 1/3 innings this season.

"I feel like this is what I'm capable of doing, going out there and keeping the ball out of the middle of the plate and keeping it down," Lohse said. "I feel like I can be successful every time out."

The 33-year-old started St. Louis' Opening Day contest in Miami on April 4, so he did not pitch in the following series at Milwaukee from April 6-8. He went 1-2 in three outings versus the Brewers last season despite a 2.37 ERA.

Milwaukee also got a bonus lift from its starter today as Marco Estrada moved into the rotation last Saturday against the Rockies due to Chris Narveson's season-ending shoulder injury and pitched excellent in his first start since the spring.

The 28-year-old righty lasted 78 pitches and five innings, giving up one run on two hits -- one a solo homer -- without a walk, striking out a career-high nine batters. The offense didn't come on until late however, leaving Estrada with a no-decision in a 9-4 win.

"He gave us a lot of innings with a lot of zeroes," said Brewers manager Ron Roenicke. "His fastball today was really lively and he had some giddyup on it. He had good off-speed stuff but his fastball was really the key."

Estrada faced the Cardinals twice in relief at the start of this season, throwing 1 1/3 scoreless innings on April 6. He posted another two innings on April 8, but was touched for a two-run homer by Carlos Beltran.

The Brewers will look for some innings from Estrada this afternoon after starter Yovani Gallardo lasted just two-plus frames while yielding eight runs on eight hits and two walks in a 13-1 setback.

"I've been throwing the ball good and to have a game like this is very frustrating," Gallardo said.

Milwaukee actually scored the game's first run thanks to three straight one- out singles, the latter by Aramis Ramirez scoring Nyjer Morgan in the first inning, but the Cardinals went ahead in the second and broke the game open with an eight-run third inning, sending the Brewers to their fifth loss in eight games.

Jon Jay and Skip Schumaker both drove in three runs, while Matt Holliday and Matt Carpenter finished with two RBI apiece in St. Louis' second straight win.

Jake Westbrook allowed one run on seven hits with no walks and five strikeouts over seven innings to earn the victory.

"It's always good to win ballgames. We've strung together some here and that's what we want to do. I think we're playing with a lot of confidence," said Westbrook.

In addition to besting the Brewers in six games in last season's NLCS, St. Louis has won nine of its past 11 over Milwaukee, including three of four so far this year.