ST. LOUIS - As a trade deadline addition, Dan Haren was unaware the Cubs had struggled in St. Louis. In the end, it was probably better he didn't know about Chicago's sorry 1-6 record at Busch Stadium.

"I didn't know we had struggled here," Haren said after working seven innings in a 9-0 victory over the Cardinals on Monday. "Everyone has struggled against the Cardinals this year; they're the best team record-wise."

The NL Central-leading Cardinals maintained a 5 1/2-game lead over Pittsburgh, which lost 3-1 to Cincinnati. The Cubs are 7 1/2 games back.

Dexter Fowler had a leadoff home run and two-run double in the first two innings.

Before the game, manager Joe Maddon said he told Fowler: "You go, we go. He gets up there and makes us go."

Fowler matched his season best for RBIs and became the Cubs' first switch-hitter to score 90 runs since Brian McRae scored 111 in 1996.

"I'm seeing the ball well, barrelling balls well," Fowler said. "The team camaraderie is awesome right now, even with the new guys coming in."

Addison Russell's three-run homer capped a five-run third that made it 8-0. The Cubs have won four in a row and got an 11-game trip off to a rocking start.

"We've got to beat them here, that's really important regarding our development," Maddon said. "So, it's a nice first step, but let's have another one-game winning streak tomorrow."

Haren (9-9) had five strikeouts and two walks. He also contributed a single and sacrifice fly.

Lance Lynn (11-9) surrendered six runs in 2 1-3 innings on nine days' rest after getting extra time to recover from a sprained ankle in his last start. The ankle wasn't the issue.

"Just didn't have any command," Lynn said. "The ball was all over the place, and when I started making pitches they were already locked in."

He wasn't happy about getting the bonus time off.

"When you're in a rhythm and a creature of habit, the extra time is never wanted," Lynn said.

The Cardinals are 3-4 on this homestand with two games to go. They're a major league-best 49-24 at Busch Stadium, but this was their most lopsided setback at home. They've been outscored 16-1 the last two games.

"I think we've been so accustomed to seeing that starting pitching so locked down that when we don't see it, it looks extremely odd," manager Mike Matheny said. "Today was one of those days."

Fowler's leadoff homer was his fifth this season and the 14th of his career.

The Cubs are 36-29 on the road, second best in the NL behind the Cardinals' 38-27.

NO FREE PASSES

Cubs starting pitchers have walked three or fewer in 65 consecutive games, the longest active streak in the majors.

TRAINER'S ROOM

Cubs: Kyle Schwarber (rib/oblique) took swings indoors and manager Joe Maddon didn't rule out the rookie for later in the series.

Cardinals: 2B Kolten Wong (calf tightness) was a late lineup scratch. He struck out pinch hitting and reached first in the ninth. Randal Grichuk (elbow) pinch ran in the ninth after being activated off the DL, but has not been cleared for hitting or throwing.

UP NEXT

Michael Wacha (15-4, 2.69) pitches for the first time since Aug. 28. He's 4-0 with a 2.88 ERA in nine career starts with six-or-more days rest. Jason Hammel (7-6, 3.55) faces the Cardinals for the third time this season. He's 1-3 with a 6.31 ERA record for his career against St. Louis.