Cruz homered twice in the first three innings, raising his major league-leading total to eight, and Jackson hit the 11th leadoff homer of his career.
The big drama came in the ninth.
Brad Miller led off with a single off Neftali Felix (0-1) and advanced on Seth Smith’s one-out walk. Jackson lined a single to right that fell in front of Shin-Soo Choo.
After Rickie Weeks’ popout and an intentional walk to Robinson Cano, Cruz lined a 96 mph pitch into left field to score Smith. Feliz had not blown a save chance since Aug. 3 at Cleveland and allowed earned runs to Seattle for the first time in 23 career appearances against the Mariners.
Seattle, which took two of three from the Rangers, trailed 7-2 and 10-5, then closed with one run in the seventh and three in the eighth.
Cruz hit a solo homer in the first and a three-run drive in the third, his first two homers this season at home. Cruz is the first player with eight home runs in a team’s first 12 games since Alex Rodriguez in 2007.
Cruz struck out in his next three at-bats, then got the seventh game-winning RBI of his career and first since 2012.
Yoervis Medina (1-0) pitched the ninth to get the victory. Seattle starter James Paxton and Texas’ Ross Detwiler failed to make it out of the third inning.
Texas scored seven runs in the third inning, sending 11 batters to the plate. Jake Smolinski’s two-run homer was the big blow of the inning. The Rangers added three more in the sixth inning, including RBI singles by Shin-Soo Choo and Mitch Moreland.
But it wasn’t enough.
Kyle Seager had an RBI single in the seventh and Tanner Scheppers walked three in the eighth. Chief Sealth High School product Keone Kela forced in run with a walk to Cano and Seager singled in two runs.
Rangers: Moreland, who missed the previous two games with a sore elbow, came on as a pinch hitter in the sixth and remained in the game at first base. Moreland flied out to the wall in left-center in the eighth.
Mariners: Catcher Mike Zunino came close to getting his first full day off of the season but caught the ninth inning after Jesus Sucre was pulled for a pinch hitter.
Rangers: Texas has an off day on Monday before opening interleague play with a two-game series against Arizona on Tuesday. Nick Martinez will start the opener.
Mariners: Hisashi Iwakuma will get the start on Monday night when Seattle opens a three-game series against Houston.