Staging a six-run rally with two outs in the fifth, the Rangers rocked John Lackey and sent the Angels reeling to an 8-5 loss in front of 42,088 at Angel Stadium.
Juan Rivera homered twice, giving him 16 for the season, but the Rangers' sudden eruption against Lackey proved insurmountable.
"I actually felt I was throwing better than it looks," Lackey said, having slipped to 3-4. "I feel great. They're playing good. They've got a good lineup, and they're pitching better and playing better defense."
Compounding the loss, the Angels watched Vladimir Guerrero walk off the field in the eighth inning, having pulled up favoring his left leg on a single to right by Elvis Andrus.
The initial diagnosis was a strained muscle behind the left knee.
"We're still in first place," Lackey said when asked if the possible loss of Guerrero again is symbolic of the Angels' struggles this season. "Let's not jump off a bridge."
Angels manager Mike Scioscia said Guerrero will be reevaluated on Wednesday and is doubtful for the series finale. The slugger missed 35 games recovering from a torn pectoral muscle after spending the winter and spring recovering from right knee surgery.
Lackey was cruising with a three-run lead when All-Star third baseman Michael Young, hustling out of the batter's box, beat out a chopper to shortstop Erick Aybar to start the two-out uprising in the fifth.
"Erick did everything he could on that play," Lackey said. "Young just beat it. He's a guy I've faced probably 100 times. It's always a tough at-bat. He's a professional hitter. He plays the game the right way. He's a guy I'd pay to see."
After Josh Hamilton's third hit of the night moved Young to third, Andruw Jones lifted a slider over the wall in left-center for his 11th homer, tying it at 3.
"At that point," Young said, "he was pitching a great game. We were fortunate to run into a big inning, because he had great stuff. He was dealing. He made a great pitch, I chopped it up the middle, and we caught a big break."
Hank Blalock's double to left was followed by two walks, Blalock scoring the go-ahead run on a wild pitch before Jarrod Saltalamacchia lined a two-run single to finish Lackey's night.
"They're a good offensive club," Scioscia said. "If you're missing your spots, they're going to let you know. I thought John's stuff was still fine. Two outs, nobody on, they kept stringing together good at-bats. John's out there competing. They put together a heck of an inning."
Lackey departed after 4 2/3 innings, yielding six earned runs on nine hits and two walks, with six strikeouts. Jason Bulger got the last out of the inning and worked a perfect sixth.
Right-hander Dustin Nippert, in his first start of the year for the Rangers, worked out of trouble in the first and second innings before yielding a run in the third.
Aybar bunted for a hit, stole second and scored on Final Vote candidate Chone Figgins' single.
Rivera led off the fourth with a towering homer to left-center. Maicer Izturis doubled into the right-field corner, scoring on Aybar's two-out single.
"We're finally getting some offensive continuity," Scioscia said. "The last 40 games or so, it's a club that's really picked it up -- so much so it's really fueling this charge to get up in the division."
A two-out fielding error by Saltalamacchia on Izturis' popup led to an unearned run in the sixth. Figgins took a bases-loaded walk before Jason Jennings fanned Bobby Abreu to leave the bases loaded.
The Angels threatened in the seventh, but C.J. Wilson left the bases loaded when Mike Napoli flied out.
Lefty Derek Holland, with two innings of scoreless relief, moved to 3-5 with the win.
Rivera's second homer, in the ninth, came against closer Frank Francisco. It was the eighth multihomer game of Rivera's career.