Cleveland starter Justin Masterson dominated Seattle's lineup with 11 strikeouts in seven shutout innings and the Mariners, who were beaten on walkoffs in the first two games of the series, barely put up a fight in dropping their third straight, 6-0 to the Indians on Sunday.
Hernandez (5-3) came in with the AL's lowest ERA, but was tagged for five runs and eight hits in a season-low five innings. He became the seventh former Cy Young winner to lose to the Indians, who have won 17 of 21 and are a baseball-best 20-7 since April 20.
"It's tough," Hernandez said. "It wasn't my day. It was a weird game."
The Mariners were in a 5-0 hole after just two innings as the Indians jumped on Hernandez for two runs in the first inning and then got a three-run homer in the second from Michael Brantley. Hernandez had allowed just four earned runs over 44 innings in his prior six outings.
"We had our guy on the mound," Mariners manager Eric Wedge said. "They did a good job against them and their guy threw a heck of a ballgame."
Staked to an early lead, Masterson (7-2) overpowered the Mariners, who didn't get a runner to third base until the ninth inning. Masterson easily outdueled Hernandez and ran his consecutive scoreless innings streak to 19. He shut out the New York Yankees 1-0 on four hits in his previous outing.
"His ball was moving all over the place," Wedge said of Masterson. "He had it all working."
The Mariners are scuffling. After winning two of three in New York and 11 of 17, they came to Cleveland on a roll. But they've dropped three in a row and had a few fundamental breakdowns on Sunday, allowing the Indians to build an early lead that seemed bigger than it was.
Hernandez didn't get much help from his defense in the first.
Michael Bourn led off with a single that he alertly turned into a double when right fielder Michael Morse casually charged the slow roller into right-center. One out later, Brantley hit an RBI single and took second when Morse overthrew his cutoff man while trying to get the speedy Bourn at home.
Nick Swisher then hit a grounder that went through first baseman Justin Smoak's legs, giving Cleveland a 2-0 lead.
"We were sloppy in that first inning defensively," Wedge said.
Hernandez, who needed 35 pitches to get through the first, retired the first two batters on groundouts in the second before Bourn singled and went to third on Jason Kipnis' base hit to center. Brantley then drove an 0-1 pitch into the Indians' bullpen in center for just his second homer.
It was a stunning development against Hernandez, who left his previous with a stiff back.
A fundamental gaffe by Hernandez allowed the Indians to add a run in the fourth. With Mike Aviles at second after a double, Drew Stubbs topped a ball into the dirt that catcher Jesus Montero fielded in front of the plate and threw to first for the out. Aviles never slowed coming around third and scored easily because Montero got caught up the line and Hernandez failed to cover home.
Wedge didn't blame Hernandez for letting Aviles score.
"It's tough," Wedge said. "There's not much you can do about it. It's a swinging bunt so they're both attacking the baseball. As soon as that ball is hit, Aviles is breaking off second base. Because the ball is so far out, they both attacked it. Monty took it. By the time either one of them tried to get back, he was already there."
The Indians are 7-1 in eight games against Cy Young winners. They've knocked off Hernandez, R.A. Dickey, David Price, Roy Halladay, Cliff Lee, Bartolo Colon and Justin Verlander.
"We just take it as a challenge," Indians first baseman Nick Swisher said. "We've got that scrappy-type and gritty-type of team. It may not always be pretty, man, but somehow we're going to find a way to get it done. We just love coming to the ballpark right now.
"Things are rocking," Swisher added.
Not for the Mariners, who haven't lost four in a row all season and will try to salvage the series finale on Monday.
"You're going to have games like that when a couple of things happen and you make a couple of mistakes," Wedge said. "That's what happened to us. It was one of those days for Felix and one of those days for us."
NOTES: Mariners RHP Aaron Harang, scratched from a start last week with a sore back, is expected to face the Angels on Tuesday after reporting no problems after a bullpen session. ... The Mariners have lost just two of the last seven series. ... Seattle has lost five straight at Progressive Field. ... White Sox RHP Jake Peavy is the only former Cy Young winner to beat the Indians this season. ... Masterson is the fifth starter to record double-digit strikeouts against the Mariners in 2013.