LOS ANGELES >> Michael Wacha pitched seven effective innings, Jason Heyward and Kolten Wong drove in two runs each, and the St. Louis Cardinals beat the Los Angeles Dodgers 7-1 on Thursday night in the opener of a four-game series between the National League’s top two teams.

The Cardinals, who knocked the Dodgers out of the playoffs in each of the previous two seasons, increased their Central Division lead to 6 1-2 games over the idle Pittsburgh Pirates while the Dodgers’ West Division advantage shrunk to 1 1-2 games over the idle San Francisco Giants.

Wacha (8-1) allowed a run and seven hits without walking a batter and had five strikeouts, five days after the Dodgers beat him 5-1 at St. Louis in a game that was delayed more than 2 hours by rain. This was the right-hander’s first road start against the Dodgers, whom he defeated twice in the 2013 NL championship series while shutting them out in 13 2-3 innings.

Wacha became the first Cardinal to begin a season 6-0 on the road since 2005, when Chris Carpenter won his first 12 decisions away from Busch Stadium and Matt Morris his first six.

Right-hander Carlos Frias (4-3) was charged with five runs — three earned — and 10 hits through 6 2-3 innings in his rematch with Wacha.

St. Louis opened the scoring in the third with two unearned runs. Jhonny Peralta and Mark Reynolds had RBI singles after a two-out fielding error by third baseman Justin Turner on Matt Carpenter’s grounder in the hole and Matt Holliday’s single. The Cardinals increased the margin to 5-0 in the fifth on Holliday’s sacrifice fly and Jason Heyward’s two-out, two-run single.

The Dodgers loaded the bases in the sixth with one-out singles by Adrian Gonzalez, Turner and Andre Ethier. Alex Guerrero hit a sacrifice fly that got the Dodgers on the board, but Jimmy Rollins grounded out to second.

Rollins has been in the bottom third of the batting order the last six games he has started, going 5 for 20 with one RBI in those games after being dropped from the 2 hole. He began his first season with the Dodgers in the leadoff spot before he was replaced there by power-hitting rookie Joc Pederson.

Los Angeles got only one runner as far as second base during the first four innings. Pederson, who homered in each of his previous five games to give him 17 for the season, doubled to left field with two outs in the third and was stranded when Yasmani Grandal flied out. In the fifth, Pederson stranded two men in scoring position when he took a called third strike.

TRAINER’S ROOM

Dodgers: Closer Kenley Jansen was cleared by the team’s medical staff to pitch, a day after the altitude in Denver caused high blood pressure, a headache and an upset stomach. … 2B Howie Kendrick was held out of the game because of a sore knee, which he hurt sliding into third base in the seventh inning of Wednesday’s game.

UP NEXT

Cardinals: RHP Carlos Martinez (5-2) hasn’t allowed a run in his last three starts, spanning 20 1-3 innings. Last Sunday he held the Dodgers to one hit over seven innings and struck out eight in a 3-1 victory, following an emotional pregame tribute to his late teammate and best friend Oscar Taveras, who was killed in a car accident in October.

Dodgers: LHP Brett Anderson (2-3) comes into his rematch with Martinez 0-2 with a 3.28 ERA over his last four starts. His last four starts at Dodger Stadium have resulted in no-decisions since his 5-2 win over Seattle on April 15.