The Angels pulled within 2 1/2 games of Texas on Monday, as Mark Trumbo hit a two-run homer and added an RBI double in a 7-3 win in the opener. Vernon Wells also homered for Los Angeles, which has won three straight and four of five, while taking advantage of the Rangers' loss to Tampa Bay.
Dan Haren (14-8) got the win after limiting Seattle to three runs on 10 hits in six innings.
"It was a battle from the get-go. I didn't have my best stuff, obviously," Haren said. "I couldn't find the release point. My offense picked me up."
Seattle rookie left-hander Anthony Vasquez (1-2), making his third career start, suffered the loss after being knocked around by the Angels again.
He had faced the Angels on August 30 and allowed eight runs -- seven earned -- in four innings. On Monday, he gave up seven runs -- six earned -- in 5 2/3 innings.
Brendan Ryan hit a homer for the Mariners, who have dropped five in a row.
"We were sloppy all day today," said Seattle manager Eric Wedge. "Vasquez deserved a better fate. We swung the bats well, a positive. Vasquez, a positive. We're still working to put it all together."
Santana, meanwhile, has been terrific for Mike Scioscia's club this season, going 11-9 with a 3.27 earned run average. The righty won his second straight start on Thursday against the Mariners, as he held them to three runs and four hits in 6 2/3 innings. He also walked seven batters, but still managed to get the win.
"It wasn't the release point," Santana said. "I just couldn't throw it where I wanted it. Location. It was bad. But I made pitches when I needed to and kept us in the game."
He is 11-5 in 24 starts versus the M's with a 3.69 ERA.
Seattle will counter with the AL's reigning Cy Young Award winner in Felix Hernandez, who is 13-11 with a 3.27 ERA. Hernandez went the distance to beat the Angels last Wednesday, as he gave up just a run and five hits in the win.
Hernandez is 5-9 lifetime against the Angels with a 3.85 ERA in 24 starts. He's been even worse at Angel Stadium, where he is 1-5 with a 3.35 ERA in 12 career starts
The Angels have won 11 of their 17 matchups with the Mariners this season, including seven of the eight meetings at the Big A.