Oakland's eighth consecutive road win kept them a half-game up in the American League Wild Card race and 4 1/2 games behind Texas in the American League West.
Coming off a five-hit, one-run outing against Boston on Sunday, Anderson was just as good, if not better, against the Mariners. But afterward, the lefty said that it was his "most grinding" start yet.
"It's always fun and easy when it's going good, but it makes these starts sweeter when you have to pitch out of jams and battle your way through it," he said.
The lefty allowed one unearned run on six hits in six innings and lowered his ERA to 0.69. The only blip in his performance came in the second inning, when a Stephen Drew error at shortstop led to a run.
Beyond that, Anderson was on point. He allowed a runner past second base just once and forced the Mariners into a flurry of ground balls and flyouts. The 24-year-old has given up two runs in four starts since coming off the disabled list for his Aug. 21 season debut.
"He looked pretty good to me," Seattle manager Eric Wedge said. "He did a good job with his fastball. He obviously has a lot of confidence in that breaking ball he throws. He controlled the tempo of the game, too."
Anderson got plenty of support from an Oakland offense that continues to deliver. The A's did most of their damage in a four-run fourth frame, batting around and forcing Seattle starter Hisashi Iwakuma out of the game. The Mariners righty had given up just four runs in his past five starts, but it was a different story on Saturday.
After a Drew RBI single gave the A's a 2-1 advantage, catcher George Kottaras took advantage of another start with his fourth home run in as many days, this time a two-run homer off an Iwakuma slider to the right-field seats that made it 4-1 Oakland.
The momentum-building homer mimicked Kottaras' home run off Felix Hernandez -- also in the fourth inning -- during Oakland's 6-1 win on Friday night.
"It seems like every home run he has hit for us has been a big one," Melvin said. "Tonight's had the same effect as last night."
"We all feed off each other," Kottaras added. "Once we get something rolling, everyone starts contributing throughout the night."
Kottaras, who started for the second consecutive game, now has 13 RBIs and four home runs in his past five games. He's part of an Oakland offense that's hitting .290 (117-for-403) over the past 11 games.
Saturday's win was Oakland's 36th on the road, its most since 2007.