Sonny Gray tries to build off the best outing in his young career on Tuesday when the Oakland Athletics continue a three-game series with the Seattle Mariners at O.co Coliseum.

Gray was magnificent against the woeful Houston Astros on Thursday, as he picked up his first big league win by scattering four hits over eight scoreless innings. He also struck out nine batters and improved to 1-1, while lowering his ERA to 1.00.

"It was good for (Bob Melvin) to have the confidence in me to leave me out there," said Gray, who threw 118 pitches in the win.

Oakland drew first blood in this series in dramatic fashion on Monday, as Brandon Moss belted a solo home run off Carter Capps in the ninth inning to propel the Athletics to a 2-1 win.

The pitchers' duel was decided on a one-out, 2-1 fastball from Capps (2-3) that Moss sent to straightaway center for his 19th home run of the year.

"Watched it about four or five times already and I felt like I executed the pitch pretty good," said Capps. "I was trying to throw a strike low and away and I did, he just got to it."

The blast secured a win for Jarrod Parker (9-6), who tossed a complete game for the first time and stayed unbeaten in his last 15 starts. Parker scattered eight hits and allowed one run while striking out eight with no walks.

"He's the guy that's pitching the best right now. We feel great about him," Melvin said. "Not only is he throwing the ball well, he's getting quick outs, which is allowing him to pitch deep in games."

Seattle starter Aaron Harang did not factor in the decision despite holding the A's to one run on five hits over seven innings.

Oakland has won four of its last five while Seattle fell to 3-4 on its nine- game road trip.

Hoping to get Seattle back into the win column on Tuesday will be left-hander Joe Saunders, who has lost four his last five starts. Saunders' most recent setback came to Tampa Bay on Thursday, as he was roughed up for five runs and seven hits in 4 1/3 frames to fall to 10-12, while ballooning his ERA to 4.86.

He has allowed 14 runs (9 earned) in his last two starts, spanning 8 2/3 innings.

Saunders, though, is 15-6 lifetime against the A's with a 3.36 ERA in 23 starts.

Seattle has the edge in the head-to-head series with Oakland this season, as the M's have won eight of the 14 meetings.