Matt Carpenter (photo/MLB)

Matt Carpenter (photo/MLB)

Matt Carpenter and the St. Louis Cardinals knocked around Clayton Kershaw in another postseason stunner.

Carpenter’s four RBI included a three-run double in an eight-run seventh inning and the Cardinals held on to beat the Los Angeles Dodgers 10-9 on Friday to open their NL Division Series.

Kershaw and Adam Wainwright squared off in the first postseason game in 45 years to feature two 20-win starters with sub-2.40 ERAs.

But what was supposed to be a pitchers’ duel between two staff aces turned into a slugfest, and Kershaw saw the worst of it.

The presumptive NL Cy Young Award winner retired 16 batters in a row between Randal Grichuk’s one-out homer in the first inning and Carpenter’s two-out blast in the sixth, and his team had a 6-1 lead after scoring six runs off Wainwright in 4 1/3 innings.

But the first four Cardinals batters hit singles in the seventh, starting a deluge that didn’t end until Kershaw was on the bench, presumably wondering how the NL Central champions got the best of him again.

Last year, Kershaw gave up seven runs in four innings in the decisive Game 6 of the NL Championship Series, which the Cardinals won 9-0 to reach the World Series for the third time in eight years.

He was the first pitcher in major-league history to give up seven runs or more in back-to-back postseason starts.

“I feel terrible. It’s an awful feeling to let your teammates down,” said Kershaw. “They were playing great, got a bunch of runs for me and I couldn’t hold it.”

The Dodgers brought the go-ahead run to the plate twice in the ninth inning against Cardinals closer Trevor Rosenthal but scored just once and stranded the tying run at third base when Yasiel Puig struck out.

Game 2 of the best-of-five series is Saturday in Los Angeles.

“We’ve been through a lot,” said Dodgers manager Don Mattingly. “I don’t think we have to defend ourselves as a team. We’ll be ready tomorrow. It was a loss tonight. It’s gotta be put behind us.”

Kershaw’s pitching line was stunning: eight runs and eight hits, but also 10 strikeouts and no walks in 6 2/3 innings. Also a strong candidate for NL MVP, Kershaw (0-1) had won his last seven starts.

Matt Holliday added a three-run homer in the seventh inning for the Cardinals, who clinched their second straight division title on the final day of the season.

A.J. Ellis had four hits for the NL West-champion Dodgers, including a two-run homer off Wainwright. Adrian Gonzalez hit a two-run homer off Randy Choate in the eighth to get the Dodgers with two.

Tempers flared in the third inning after Wainwright hit Puig in the arm. The next batter, Gonzalez, jawed with catcher Yadier Molina, causing the benches and bullpens to clear, though no punches were thrown.

The bad blood dates to Game 1 of the NLCS last year when Dodgers star Hanley Ramirez was hit in the side, and was bolstered by several bean-ball incidents this season.

Matt Adams hit the fourth straight single for the Cardinals in the seventh, knocking in the first run. Jon Jay added a one-out RBI single and Carpenter fouled off five pitches before stroking his double off the right-center field wall, changing the tone of the game.

“They got a couple guys on base and they gained confidence really fast,” said Kershaw.

Cardinals manager Mike Matheny explained the rally as his players taking a simpler approach against Kershaw and not trying to do too much.

“And then you just hope someone comes up with a big hit,” he said.

Carpenter had a double off Kershaw to spark a four-run third inning last year in Game 6. On Friday, he said he was just “trying to keep the line moving” in a big inning.

“I was able to get a pitch I could handle and get the barrel on and hit into the gap,” he said.

Holliday hit his 13th career postseason home run off Baez, drawing a pained look from Kershaw in the dugout as the Cardinals turned a 6-2 deficit into a 10-6 lead.

After Puig drew a one-out walk off Carlos Martinez in the eighth, Gonzalez hit a 1-1 slider to right-center to get the Dodgers within two run and Dee Gordon had an RBI groundout in the ninth.

The Dodgers scored after Puig was hit in the third, sparking a two-run rally.

The two-out runs came on Ramirez’s single and Carl Crawford’s ground-rule double. Puig and Matt Kemp added RBI singles in a two-run fourth and Ellis chased Wainwright with his homer to left in the fifth, which made it 6-1.