ANAHEIM, Calif. -- It all unraveled quickly on Ryan Dempster.

A leadoff single, a walk, a sharp groundout. Then a loud, two-run single off the right-field wall, another walk, and that was it. Texas Rangers manager Ron Washington had seen enough.

For the first time since his less-than-stellar debut Aug. 2, Dempster failed to toss at least six innings as the Los Angeles Angels took the opener of the three-game series, 11-3, Tuesday night.

"It got out of control," Washington said of the wacky fourth inning. "We couldn't get any outs."

Dempster had won six of his previous seven starts, but struggled against the same Angels he faced on his first outing as a Ranger. The 3 1/3 innings he threw Tuesday were a season-low, including his time with the Chicago Cubs.

"I could have done a better job of finishing guys once I got ahead of them," Dempster said.

Dempster had troubles from the start, needing a double play to escape a jam in the second and then wiggling out of a bases-loaded situation in the third. It all caught up with him in the fourth, with Vernon Wells leading off with a sharp single and Alberto Callaspo drawing a walk. Two batters later, Chris Iannetta lined a two-run single off the scoreboard in right field before Mike Trout walked. Up until that point, it was a ballgame.

"He didn't have his good breaking ball, he didn't have his good change up, he didn't have his good sinker," Washington said of Dempster. "It was a struggle all night."

But of course, it wasn't all on Dempster.

Tanner Scheppers relieved Dempster but only threw two pitches before leaving with a knee injury. His first pitch hit Erick Aybar to load the bases. His second pitch bounced past catcher Mike Napoli, allowing Iannetta and Trout to score, the first of which slid into Scheppers as he covered home plate. Scheppers hobbled off the field with the help of trainers, but the bottom of the inning -- which had started with the Rangers leading 3-1 -- was far from over.

Lost in all of this was the fact that Josh Hamilton didn't take the field in the fourth due to what the club described as "sinus issues" and "vision troubles." By the time that had sunk in, it all unraveled on the Rangers. The Angels sent 12 men to the plate and scored eight times, a season-high for them at home this season.

"Bottom line is they had some good at-bats that inning," Michael Young said. "It was a huge inning and obviously the turning point of the game. Demps has been great since he's been here before losing that start. [The Angels] just had some good at-bats. Demps is a vet and knows how to make good adjustments. I'm sure in his next start he'll be great."