And when it's Barry Zito on the mound against the Mariners, victory is almost assured.
Zito overmatched Seattle yet again, and A's won their 10th straight over the Mariners with a 5-2 victory on Friday night.
With the teams separated by just 3½ games in the AL West entering Friday, Zito pitched seven innings, allowing one run and seven hits, as the first-place A's won for the fifth time in six games.
It was a giant dud for the Mariners, starting what many consider the most important series for the franchise since 2003, the last time they were in a pennant chase.
"I can't explain it at all. I look at their players and they're a good team," Oakland manager Ken Macha said. "It's tough to put your finger on it."
After dropping its first game to Seattle on April 6, Oakland has won every matchup since, including two three-game sweeps in Oakland. The A's were 12-6 against Seattle last season.
Zito's almost equally dominant. The left-hander improved to 12-2 in 22 career starts against Seattle and lowered his ERA against the Mariners to 3.49, even though his scoreless innings streak against them ended at 21.
Zito (12-7) wasn't sharp early, but pitched his way out of trouble with some key double plays, as Seattle left six runners on base over the first four innings.
In the fifth, Zito got a huge momentum boost from a pitch that slipped. Jose Lopez led off with a single. Seattle tried to hit-and-run with Adrian Beltre at the plate. Zito threw a curveball that "squirted" out of his hand and came to the plate very high. Beltre swung and missed and Lopez was easily thrown out trying to steal.
Zito then retired the last eight batters he faced.
"That was huge. That was a momentum shift," Zito said. "Something like that happens and it sparks you. We have new life now and you have to roll with it."
In two previous starts against Seattle this season, Zito didn't allow a run, and combined with three relievers to one-hit the Mariners on April 8. The former AL Cy Young winner won for the fourth time since the All-Star break.
Zito got all the offense he needed from Marco Scutaro, who had three hits, including his fourth homer of the season with two outs in the eighth off reliever Julio Mateo.
Scutaro, filling in at shortstop for the injured Bobby Crosby, also hit an RBI double in the fourth and singled in the sixth.
"I've been playing lately a lot, and seeing a lot of pitches and feeling better," Scutaro said. "When you score some runs for Barry, it's pretty much a win."
Seattle starter Jarrod Washburn (5-11) battled through control problems to keep the Mariners close, but still lost for the fourth time in his last five decisions and missed an opportunity to win consecutive games for the first time with Seattle.
Washburn walked three, hit two batters and allowed four runs in seven innings.
"Ten straight is a little ridiculous. It's one of those things you can't explain," Washburn said. "We haven't played terrible or played scared against them, they have just played better than us."
The A's took the lead for good in the fourth. Eric Chavez and Bobby Kielty led off with singles and Scutaro doubled over the head of left fielder Raul Ibanez to score Chavez.
Mark Ellis was hit in the back by Washburn's next pitch to reload the bases. Jason Kendall then grounded into a double play, but Kielty scored for a 3-1 Oakland lead.
Oakland added a run in the seventh, when Kendall scored on Frank Thomas' two-out, two-strike single to left. Kendall beat Ibanez's throw home. Jay Payton doubled and scored on Ellis' two-out single in the second for the A's first run.
Zito's scoreless streak against Seattle ended when Ibanez, hitting .378 with two outs and runners in scoring position, lined a single to left scoring Willie Bloomquist from third. Richie Sexson hit his 24th homer in the ninth off Justin Duchscherer.
"Do we want to beat Oakland? You bet," Seattle manager Mike Hargrove said. "September is a long way off ... and we have to pay attention to tomorrow."
Zito has not lost to Seattle since July 23, 2003. ... Seattle's last run off Zito was a homer by Ichiro Suzuki to lead off the game on June 28, 2005. ... Oakland placed Crosby on the 15-day DL with a lower back strain. IF D'Angelo Jimenez was called up from Triple-A Sacramento to take Crosby's roster spot. ... Oakland's Mark Kotsay extended his hitting streak to 11 games with a single in the first inning.