Updated

Matt Tuiasosopo extended his unlikely power surge with a three-run homer, and the Seattle Mariners beat the Baltimore Orioles 6-5 Wednesday night for their season-high fourth straight series win.

Tuiasosopo's drive off Jeremy Guthrie (7-12) in the second inning put Seattle ahead for good. Tuiasosopo, a seldom-used utility player, has two homers and seven RBIs over the last two nights after totaling one homer and two RBIs in his first 30 games.

He also prevented the tying run from scoring in the eighth, making a diving catch of a two-out liner to left by Matt Wieters with Adam Jones running from first base on the pitch.

David Pauley (2-4) allowed four runs and five hits in six-plus innings to win his second straight start after opening his big league career with seven consecutive losing decisions.

David Aardsma worked the ninth for his 24th save. After Cesar Izturis reached second with one out, Aardsma struck out Brian Roberts and retired Nick Markakis on a comebacker.

The Mariners took two of three from Baltimore, their third consecutive series win under interim manager Daren Brown, who took over for Don Wakamatsu after the Mariners captured a three-game set against Kansas City.

Wieters homered and Luke Scott went 2 for 3 with two RBIs for the Orioles, now 10-6 under manager Buck Showalter.

Guthrie gave up six runs, five earned, and eight hits in eight innings. He won his previous three starts and had a 1.52 ERA over his last six outings.

Wieters' two-run shot chased Pauley and made it 5-4 in the seventh.

Casey Kotchman hit an RBI double for Seattle in the eighth, but Baltimore got a run back in the bottom half when Scott doubled off Jamey Wright, took third on a balk and scored on a wild pitch.

Tuiasosopo prevented further damage with his outstanding catch in left.

After a two-run single by Scott put the Orioles ahead in the first inning, Seattle went up 3-2 in the second. Guthrie gave up two hits, got two outs, then served up a 2-1 slider that Tuiasosopo sent into the left-field seats.

The Mariners made it 5-2 in the fifth. Josh Wilson hit a leadoff single and scored on a double to right by Ichiro Suzuki, who continued to third when Markakis bobbled the ball. Chone Figgins followed with a sacrifice fly.

NOTES: Seattle won the season series 6-3. ... Suzuki stretched his hitting streak at Camden Yards to 12 games. ... Baltimore fell to 17-5 in one-run games at Camden Yards.