Weaver (15-2) had won nine straight outings. He fell one shy of Chuck Finley's 1997 franchise record for consecutive starts won.

Vargas (13-8) allowed a run and seven hits over 8 1-3 innings. The left-hander gave up a one-out triple in the ninth by Howie Kendrick before Tom Wilhelmsen came in and got the final two outs for his 16th save in 18 chances.

Weaver was 6-0 with a 2.23 ERA and 26 strikeouts in six starts during July, but Vargas beat him out for AL pitcher of the month honors with a 5-0 record, a 1.64 ERA and 26 strikeouts in his six starts.

Weaver and Vargas, both of whom were drafted in 2004, started against each other two other times in the majors -- both last season. Vargas won the first matchup 3-0 at Seattle, and neither pitcher got a decision the second time around as the Angels won 1-0 in 10 innings.

Montero hit a solo homer in the second that landed barely beyond the fence and just over the glove of center fielder Mike Trout, who robbed Miguel Olivo of a homer in the Mariners' 7-4 win Saturday night.

It was Seattle's only hit until the sixth, when John Jaso singled with two out and Montero sent a drive into the lower seats in the left-field corner for his 12th home run. It was the second multihomer game in the majors for the former Yankees catcher, who hit two against Baltimore's Jim Johnson last Sept. 5 at New York in just his fourth big league contest.

Weaver was charged with three runs, four hits and three walks in seven innings and struck out five. It was only the second time in the right-hander's last 13 outings that he gave up more than two earned runs. His ERA increased from 2.13 to 2.22.

Angels pitching coach Mike Butcher was ejected by plate umpire Mike Estabrook just three batters into the game for complaining too loudly from the dugout about a second straight borderline pitch by Weaver that was called a ball -- resulting in a walk to Kyle Seager.

The ejection was Butcher's fourth in the big leagues and first since April 28, 2008.

Former Angel Chone Figgins, who singled as a pinch-hitter for Mike Carp in the sixth inning, drove in Seattle's final run with a ninth-inning triple against Ernesto Frieri.

NOTES: This was the first time Weaver gave up two home runs in a game to the same player since Oct. 1, 2010, when the Rangers' Mitch Moreland hit a pair of solo shots off him in Texas. ... Vargas has allowed one home run over his last five starts, after giving up at least one in each of his previous 12 -- including five on June 20 in a 14-10 loss at Arizona. ... The Mariners finished their road trip 3-6, after winning the final seven games of their previous homestand against Kansas City and Toronto. ... Weaver walked more than two batters for only the fourth time this season.