NEW YORK (AP) ― Delmon Young doubled home the go-ahead run in the 12th inning after New York’s Raul Ibanez hit another stunning game-tying home run during a four-run rally in the ninth, and the Detroit Tigers outlasted the Yankees 6-4 Saturday night in an AL championship series opener in which Derek Jeter was helped off the field with what appeared to be a serious leg injury.

Jeter rolled over his knee when he dove in an attempt to glove Jhonny Peralta’s grounder up the middle in the 12th. Unable to move, he flipped the ball toward the mound. His leg was dangling as he was assisted to the dugout by manager Joe Girardi and trainer Steve Donahue.

Detroit was coasting to a 4-0 win before the Yankees rocked Tigers closer Jose Valverde in the ninth.

Three batters after Ichiro Suzuki hit a two-run homer off Valverde to cut the Yankees’ deficit in half, Ibanez connected for his second tying drive of this postseason, a two-run shot to right-center.

Ibanez started his powerful week pinch-hitting for Alex Rodriguez against Baltimore Orioles closer Jim Johnson in the ninth inning on Wednesday to send Game 3 of the division series to extra innings. He won it with a homer in the 12th inning.

The 40-year-old Ibanez also homered twice after entering as a pinch hitter on Sept. 22 in a 10-9, 14-inning win over Oakland. With New York fighting for the AL East title, he hit a tying pinch homer against Boston in the ninth on Oct. 2 and then singled in the winning run in the 12th.

Russell Martin singled leading off the ninth on Saturday and advanced on defensive indifference. Suzuki followed with the first postseason homer of his career after Jeter struck out. Robinson Cano also struck out and Mark Teixeira walked ahead of Ibanez’s shot.

Valverde blew a save in Game 4 of the division series against Oakland and has allowed seven runs in 2 1/3 innings this postsesaon.

The Tigers opened a 4-0 lead against Yankees starter Andy Pettitte and Derek Lowe.

Prince Fielder singled in a run after Miguel Cabrera was intentionally walked in the sixth, and Young followed with another run-scoring single to make it 2-0.

Young then homered in the eighth, and rookie Avisail Garcia had an RBI single three batters later off Boone Logan to give the Tigers a 4-0 lead.

Jhonny Peralta made two difficult plays to deny the Yankees with the bases loaded in each of the first two innings against starter Doug Fister.

Peralta made a diving, backhand stop in the hole of Rodriguez’s grounder in the first, then made a nice play an inning later on Robinson Cano’s liner that caromed off the inside of Fister’s right wrist, a play that ended another bases-jammed threat.

Fister worked out of big trouble in the sixth, too. With runners on second and third, the right-hander struck out Rodriguez, and then fanned Curtis Granderson and Martin on breaking pitches after the Yankees loaded the bases.