OAKLAND — Jon Lester did just about everything the Oakland Athletics had hoped he would do in big games against big pitchers during the season's stretch run.

The A's just didn't do enough for him — again.

The troubling trend of support for Lester continued in Oakland's 2-1 loss to Felix Hernandez and the Seattle Mariners on Wednesday, dropping the three-game series to another AL playoff contender.

Kyle Seager and Corey Hart homered leading off the seventh inning as the Mariners rallied past Lester, who was acquired from Boston for slugger Yoenis Cespedes at the non-waiver trade deadline. Lester has not won since Aug. 12.

In his last four starts, the A's have given Lester three runs, two runs, no runs and one run of support.

"Guys go out there and compete, guys have good at-bats. We're competing on the mound. We're in just about every game. There's nothing more you can really ask for," Lester said. "Sometimes you just get beat and the ball doesn't fall your way."

The homers that erased an otherwise brilliant performance by Lester (13-10) and helped Hernandez (14-5) win for the first time in four outings.

Adam Dunn's homer in the fourth accounted for the only run Hernandez allowed in eight innings. The right-hander gave up three hits, struck out four and walked two to outduel Lester in a matchup of two of the AL's best pitchers.

The Mariners tagged Lester for seven hits in eight innings. Fernando Rodney pitched a perfect ninth for his 41st save in 44 chances.

"It came as advertised," A's manager Bob Melvin said. "Basically three swings of the bat, and they got two of them."

Hernandez improved to 19-7 against Oakland, including 4-0 in five starts this season, which will give the Mariners plenty of confidence should the teams meet in the AL wild-card game.

Hernandez said he's just happy to finally be pitching in a playoff race against another top pitcher.

"It was special," said Hernandez, adding that he promised his wife a win for her birthday. "We came here to win the series and that's what we did."

The A's have lost seven of nine, including a four-game series at the AL West-leading Los Angeles Angels before dropping two of three to Seattle at the Coliseum. The Mariners remain right behind Detroit and Oakland in the chase for the AL's two wild cards.

And for most of the sun-splashed afternoon, it looked like a possible preview for that game.

Hernandez, who allowed a career-high four home runs in his last start against the Washington Nationals, returned to his dominant ways for all but one pitch. It was Dunn's second homer in three days since being traded from the Chicago White Sox, his 22nd this season and 462nd of his career, tying him with former A's slugger Jose Canseco for 34th in major league history.

Lester looked to be in his All-Star form, scattering hits and keeping batters off balance, but Seattle changed that on the left-hander's first three pitches of the seventh.

Seager and Hart hit back-to-back homers to give the Mariners the lead. It was Seager's 22nd home run this season, tying a career high, and Hart's fifth.

"Two mistakes, two solo homers," Lester said. "Nothing else really to talk about as far as the game went for me."