SEATTLE -- Power pitching worked well for the Mariners in their first two victories against the Athletics.

Finesse did the trick in their series-sweeping win Thursday night.

After watching fellow right-handers Felix Hernandez and Brandon Morrow use hard stuff to subdue what had been a hot-hitting Oakland team, rookie right-hander Doug Fister relied on less power and some pinpoint control in the Mariners' 4-2 victory before 16,607 at Safeco Field.

"I just have to go out there and focus on location and not worry about what the radar gun says," the lanky hurler said after ending a personal three-game losing streak. "It was about making adjustments and keeping the ball down."

He did both and ended the regular season on a high note.

"It was like old times," catcher Adam Moore said. "We were talking about it last night, going out there and going seven strong, and that's what he did. He threw the ball well all night. It was typical Fister stuff. He was phenomenal tonight."

None of the 103 pitches Fister threw reached the 90-mph mark. But the movement and precision more than made up for any lack of zip.

"People talk about his velocity, but do you know what? If you can spot the ball the way he does and mix speed, I don't think velocity is that big of a deal."

Moore should know. He has caught Fister for the past three seasons and they were battery mates at Double-A West Tennessee and Triple-A Tacoma this season before being reunited in Seattle last month.

"We mesh well together," Fister said. "We were on the same page and it worked out."

Fister surrendered five hits, walked one and struck out four in his seven innings.

"This Oakland team came in swinging awfully effective," Mariners manager Don Wakamatsu said. "They had some great games against Anaheim and Texas before this series, and I'm awfully proud of the pitching performances to negate that. Morrow yesterday, Felix the first night and tonight with Fister."

Third baseman Adrian Beltre drove in two runs, one of them on his eighth home run of the season, and Mike Sweeney drove in two runs with a single in the fifth inning as Seattle won the season series against its American League West counterpart, 14-5.

Fister went the first seven innings, holding the Athletics to one run. Mark Lowe pitched a scoreless eighth inning. Closer David Aardsma surrendered a solo home run to Jack Cust to start the ninth inning, but retired the next three batters to notch his 37th save.

"It was nice to get Lowe and Aardsma back in there," Wakamatsu said. "It seems like we haven't had an opportunity in a while to get those guys back-to-back to finish out a game."

The 37 saves for Aardsma ties Kazuhiro Sasaki for the third-highest single-season total in franchise history. If he can save all three games against the Rangers this weekend, he would join Sasaki and J.J. Putz in the 40-save club.

It also would give the Mariners a share of second place in the AL West with the Rangers.

The Athletics helped Seattle's cause in a decisive fifth inning of the series finale.

A two-out error by third baseman Adam Kennedy opened the door to a three-run Mariners rally that snapped a 1-all deadlock

With runners on first and second, Kennedy mishandled Jose Lopez's grounder and Sweeney drove a single into right-center to score two runs. Beltre added an RBI single in the inning.

"We made one mistake in the field and they capitalized on it, big-time," Athletics manager Bob Geren said. "That was the difference."

Beltre, finishing out his five-year contract with the Mariners, put Seattle in front with a solo home run in the second inning, a 428-foot blast into the bleachers in right-center field. It was his eighth home run in an injury-plagued season.

The last time he hit this few home runs in a season was in 1998, his rookie season with the Dodgers. He had seven circuit clouts in 195 at-bats that season and at least 20 in seven of the past nine seasons -- including 95 with the Mariners before 2009.

Going into the final weekend of the season, Beltre ranks first on the franchise's all-time list for third basemen in hits (748) and extra-base hits (281), and is second in home runs (103) and RBIs (395).

The Athletics ended a 12-inning scoreless streak in the fourth inning, when Kurt Suzuki led off with a triple and scored on Daric Barton's one-out double to right.

But that was the extent of the damage against Fister, who finished the season with a 3-4 record a 4.13 ERA.

"You look at going into next spring with a belief system and it's nice already to have Fister pitch some great games in his first year against Anaheim, the Yankees and now against Oakland," Wakamatsu said. "It's an awfully good feeling to take into the winter."