Hernandez (12-3) struck out eight and walked one. His earned run average dropped to a league-leading 1.97.
Alex Wood (7-9) worked six innings, allowing five hits, just one earned run, walked four and struck out five for the Braves, who have lost seven in a row.
Fernando Rodney allowed a run in the ninth but earned his 31st save in 34 opportunities.
Hernandez also tied Gaylord Perry's 1974 streak of 15 straight starts with at least seven innings and allowing two or fewer earned runs.
During his streak Hernandez is 8-2. His teammates had scored just 10 runs over his previous five starts when he went 1-1 with three no-decisions.
A fourth-inning error by Braves second baseman Tommy La Stella contributed directly the Mariners go-ahead runs. With the score tie at 1-all, two outs and runners on second and third, Chris Taylor popped up behind the first-base bag. La Stella camped under it, leaned back and it caromed off his glove.
Both runners scored and Taylor advanced to second. He scored on Austin Jackson's single to left.
In Interleague play, Hernandez has a 17-7 record and is 5-0 with a 1.20 ERA over his last eight starts against National League teams. He has the best ever ERA in Interleague play 2.54.
Braves manager Fred Gonzalez, OF Justin Upton and 3B Chris Johnson were among eight Braves personnel who visited the Seahawks training camp during Monday's off day. "I got to spend time with Coach (Pete) Carroll a little bit. That was really cool," Gonzalez said. "We talked a little philosophy afterward. It's a different shaped ball but you're still leading men, still managing people." QB Russell Wilson, who signed a minor-league deal with the Texas Rangers this year, also spent time talking with Upton and Johnson.
KING'S FULL COURT
Whenever Hernandez pitches at Safeco Field, yellow-shirted fans fill the third-base-side lower desk, flashing 'K' signs and chanting when the batter has two strikes. A huge turkey leg, arriving on a silver platter, also is passed around to be consumed by the subjects. Six sections were filled Tuesday, most ever in the lower bowl. The MLB Network filmed the experience to show for a future show.
Mariners: OF Michael Saunders (strained left oblique) was expected to go through the full array of drills to determine his fitness. He has been on the DL since July 11. "My hope is that Michael will be able to go out on (rehab) Thursday," Manager Lloyd McClendon said.
Braves: SS Andrelton Simmons had to leave the game with one out in the fourth inning when he sprained his left ankle covered the third-base bag. Ramiro Pena replaced him. Simmons will be reevaluated Wednesday