Clayton Kershaw shanks it again for Dodgers in 10-9 loss to Cardinals

His back against a wall in a hallway outside the Dodgers clubhouse, Clayton Kershaw couldn’t offer an explanation for what happened Friday night.

In his most important start of the season, the best pitcher on the planet failed.

Again.

The playoffs started for the Dodgers this year the way they ended last year, with Kershaw ambushed by the St. Louis Cardinals.

The Dodgers dropped the opening game of their National League division series, 10-9, as Kershaw unraveled spectacularly in the seventh inning in front of a shocked crowd of 54,265 fans at Dodger Stadium.

The Cardinals scored eight times in that inning, which began with the Dodgers leading, 6-2. Six of those runs were charged to Kershaw.

The last batter he faced was Matt Carpenter, who delivered a three-run double to right-center that moved the Cardinals in front, 7-6. Two batters later, Matt Holliday hit a three-run homer off of reliever Pedro Baez to make it 10-6.

“It’s an awful feeling to let your teammates down,” said Kershaw, who was charged with eight runs in all. “They are playing great, got a bunch of runs for me. I couldn’t hold it. It’s a terrible feeling. As a starting pitcher, it’s your game to lose. I did that.”

Kershaw became the first pitcher in history to be charged with seven or more earned runs in multiple postseason starts, according to the Elias Sports Bureau. The first time it happened to him was last year in a loss to the Cardinals in the clinching Game 6 of the NL Championship Series.

The temperature was 92 degrees when Kershaw unleashed his first pitch of the game at 3:39 p.m., but the left-hander said fatigue wasn’t responsible for his implosion.

Kershaw also dismissed the idea that he might have tipped his pitches when working out of the stretch. Because the only two hits he gave up in the first six innings were home runs, he had pitched entirely from a full windup until the seventh inning.

“That’s discrediting their team when you start thinking about that,” Kershaw said.

Catcher A.J. Ellis also didn’t think the Cardinals knew what Kershaw was about to throw them.

“If that’s the case, it’s a well-kept secret,” Ellis said. “Only one team in the National League has it.”

The disastrous inning started with an innocent-looking single to center field by Holliday. Jhonny Peralta and Yadier Molina followed with singles to load the bases.

Matt Adams delivered a fourth consecutive single, to center field, to drive in a run that reduced the Dodgers’ lead to 6-3.

Kershaw struck out Pete Kozma, but his 99th pitch of the game was slapped into left field by Jon Jay for another run-scoring single. The lead was down to 6-4.

Manager Don Mattingly visited Kershaw on the mound, but only to confirm he had something left.

“His look and his face and his answer was confident and, really, that’s all I needed to hear,” Mattingly said.

Kershaw remained in the game and struck out pinch-hitter Oscar Taveras on three pitches.

With two outs and the bases still loaded, up came Carpenter, who’d homered in the previous inning.

Kershaw moved ahead in the count, 0-2, on a couple of 95-mph fastballs. But he couldn’t finish Carpenter, who ended the eight-pitch at-bat with a long drive off the wall in right-center.

Three runs scored. The Cardinals were in front, 7-6, on their way to 10-6. Kershaw’s afternoon was over, as a silence came over Dodger Stadium.

“I left some fastballs over the middle of the plate, they got some good hits,” Kershaw said. “That’s what they do. They ride momentum.”

The Dodgers scored twice in the eighth inning and once in the ninth, but Cardinals closer Trevor Rosenthal ended the game by striking out Yasiel Puig with Andre Ethier on third base.

“If I don’t get in the way, we have a pretty good chance to win that game,” Kershaw said.

Particularly in light of how the Dodgers attacked Cardinals ace Adam Wainwright.

The Dodgers went ahead, 2-1, in the third inning, which started with Wainwright hitting Puig on the top of his shoulder

Adrian Gonzalez, who was in the on-deck circle, exchanged words in Spanish with Molina, the Cardinals catcher.

The Cardinals fractured Hanley Ramirez’s ribs with a fastball in Game 1 of the NLCS last year. When the Dodgers visited St. Louis this summer, Puig was hit by a pitch. Ramirez was hit twice the next day.

“I was basically saying, ‘You guys keep doing this over and over. We’re not going to put up with that,’” Gonzalez said.

Gonzalez said Molina told him, “You have to respect me.”

The benches cleared, the bullpens emptied and both teams were warned by the umpires.

The Dodgers responded by scoring two runs that inning. They also scored twice in the fourth and twice in the fifth.

“It doesn’t feel good right now,” Kershaw said. “I don’t think it will feel good for the rest of the night. Hopefully, I get another chance.”

dylan.hernandez@latimes.com

Twitter: @dylanohernandez