Hernandez left after pitching four-hit ball, leading the Seattle Mariners over the Brewers 2-0 Sunday.
Hernandez (12-5) struck out nine and walked one in his first career appearance against Milwaukee. The 2010 AL Cy Young winner leads the league with a 2.28 ERA and is second with 178 strikeouts.
This was the eighth time this year that he pitched at least eight innings. He was on track for his possible 10th career shutout, but a 20-pitch eighth inning pushed his pitch count to 108.
Acting Mariners manager Robby Thompson visited with Hernandez between innings and determined "he was at the end of his rope."
Said Hernandez: "I'm just being honest. I don't want to go out there, tired and lose the game."
Hernandez improved to 16-7 with a 2.63 in 30 career interleague starts, including 3-0 with a 1.16 ERA in four starts this season.
Danny Farquhar worked the ninth for his fourth save.
Wily Peralta (8-12) pitched a complete game and allowed four hits. He walked none and struck out four.
Justin Smoak hit a solo home run in the fifth, his 13th.
Hernandez allowed just one hit over his first five innings, a second-inning double by Juan Francisco. He was left stranded at third.
The Brewers had two hits in the sixth but still sent only three batters to the plate.
"He still throws them out," Hernandez said. "Unbelievable."
The Mariners, who lost the first two games in the series, ended a 12-inning scoreless streak with a gift run in the third.
On a 1-0 pitch to Blanco, Peralta bounced a fastball in front of the plate. The wild pitch caromed off catcher Martin Maldonado's shoulder and rolled several feet away. Ackley sprinted home for a 1-0 score.
Brewers manager Ron Roenicke added that Hernandez "is one of the best pitchers in the game for the few years now."
"Wily was really good. Really should have given up one run," he said.
Mariners manager Eric Wedge, who has missed 18 games recovering from his July 22 mild stroke, visited the team before the game. He said he hopes to manage again when the team returns for its next homestand Aug. 23. ... Acting manager Robby Thompson said Mariners pitcher Hisashi Iwakuma "jammed" his back Saturday against the Brewers. "I talked to him a little bit. He said he was fine. He should be good to go," Thompson said. ... The Brewers this weekend became the final Major League Baseball team to play a regular-season game at Safeco Field. Before Friday, the last time Milwaukee played a regular-season game in Seattle was Aug. 12, 1997, at the Kingdome. ... The Brewers' franchise actually began in Seattle. After one season as the expansion Seattle Pilots, the club moved to Milwaukee to play as the Brewers in 1970.