Haren pitched three-hit ball into the eighth inning, and Matt Kemp homered in the Dodgers' 2-1 victory over the Los Angeles Angels on Wednesday night.
Haren (9-9) retired the Angels' first 16 batters in his best start since June for the NL leaders, who improved the majors' best road record to 35-23 by beating the majors' best home team.
"I tried almost everything, and it finally started working a little bit," Haren said.
He had lost his last five starts with a 10.03 ERA, leaving him despondent after games, but the former Angels right-hander was dominant at the stadium where he played from 2010-12.
"It was nice to take him out of a game with a smile on his face instead of feeling like he let everybody down," Dodgers manager Don Mattingly said.
Haren's bullpen also helped him out — particularly his closer.
Kole Calhoun singled and stole second leading off the ninth, but Jansen struck out Mike Trout, got Albert Pujols on a fly to center and struck out Josh Hamilton to wrap up his 32nd save.
"Jansen made good pitches when he needed to against three of our best hitters," Angels manager Mike Scioscia said. "We didn't do nearly what we needed to do to support Matty Shoemaker. I thought he gave us a good chance to win."
Shoemaker (9-4) yielded six hits and struck out five over six solid innings for the Angels.
Andre Ethier had an RBI double in the second inning as the Freeway Series moved down the I-5 to Anaheim after the clubs split the first two games in Chavez Ravine.
Erick Aybar singled and scored in the eighth for the Angels, who missed a chance to move within one game of MLB-leading Oakland in the AL West.
Hank Conger's one-out single in the sixth was the Angels' first hit.
"With a guy like him, you kind of disregard his past starts," said Conger, who caught Haren several times when they were teammates. "Because any day he could step on the mound and do what he did tonight. He's been an elite pitcher for a long time."
Haren left in the eighth after giving up a single to Aybar, who scored on Chris Iannetta's long fly off Brandon League.
Kemp hit his sixth homer in nine games in the second inning, a 400-foot shot to left. Ethier followed with a run-scoring double in only the high-priced outfielder's second start in 13 games.