Hernandez (3-0) struck out 11 and shut down Oakland for the second time in a week, becoming the first Mariners pitcher to win three times in the first nine games of a season.
With the usual ''King's Court'' for Hernandez home starts expanded to a ''Supreme Court'' encompassing the entire stadium with yellow shirts and ''K'' cards, Hernandez gave up four hits in the 28th double-digit strikeout game of his career.
Zunino chased starter Tommy Milone (0-1) with a two-run shot in the sixth. Miller followed two batters later with a solo homer to center field with the wind blowing in.
Hernandez was charged with two runs and walked none. He has 30 strikeouts against two walks in his three starts.
Hernandez's first home start of 2014 was his best performance in the young season. All three of Oakland's four hits off Hernandez came in the span of five batters in the fourth and fifth. Jed Lowrie's one-out single in the fourth was Oakland's first hit, and Josh Donaldson followed with an infield single. Hernandez pitched out of the jam with strikeouts of Brandon Moss and Yoenis Cespedes.
Hernandez struck out the side in the seventh, but Daric Barton was hit on the foot by a curveball and Eric Sogard singled to open the eighth. That was it for Hernandez, and Seattle's bullpen was shaky.
Lucas Luetge walked his only batter. Danny Farquhar walked Lowrie on a 3-2 pitch to score Barton. Brandon Moss added a broken-bat single off Charlie Furbush for the second run charged to Hernandez, and Cespedes beat out a potential double play to score another. Furbush threw a wild pitch that Fuld scored on to cut the deficit to 6-4, but Callaspo popped out to end the rally.
Fernando Rodney pitched the ninth for his third save.
The Mariners needed only three pitches to get to Milone, who was making his first start of the season after postponements caused his turn to be skipped. Abraham Almonte doubled on the first pitch of the game, Miller followed with a bunt single and Cano's infield hit gave Seattle a 1-0 lead.
Seattle appeared to add another in the fourth when Kyle Seager was ruled to have hit a solo homer down the right field line. The play was reviewed by umpires and the ball was called foul. But Seattle scored twice in the inning when Donaldson and Lowrie committed two-out errors after Dustin Ackley's double.
Milone gave up 10 hits and three earned runs in his season debut.
NOTES: Oakland OF Coco Crisp did not start for the fourth straight game due to a sore wrist. He pinch-hit in the ninth. ... The A's will likely activate OF Craig Gentry from the disabled list Saturday, manager Bob Melvin said. ... Ackley became the first Seattle batter with three hits in a game this season. ... Seattle is still unsure of its starter for Tuesday in Texas. Manager Lloyd McClendon expected a decision before Saturday's game. Likely options are RHP Blake Beavan coming up from Triple-A or RHP Taijuan Walker being activated from the DL.