Oakland wound up eliminating the Angels anyway with a 4-3 victory against Texas that clinched an AL Wild Card berth for the A's, while the Angels are assured of a third-place finish in the AL West now at 89-71 with two games to go.
Seattle is 73-87 heading into its two final games with the Angels, with Hernandez now done for the year with a 13-9 record and 3.06 ERA.
The Mariners ace blazed into September on a nine-game win streak and angling for his second American League Cy Young award with a perfect game and five shutouts to his credit, but wound up getting stuck on 13 wins after going 0-4 with a 6.62 ERA and 53 hits in 35 1/3 innings in his final six starts.
He was 0-3 with a 6.25 ERA in five shots this year at the AL West-rival Angels, 13-6 with a 2.56 ERA in 28 starts against the rest of baseball.
That's nothing new, however, as Hernandez is 6-12 with a 4.07 ERA in 30 starts in his career against the Halos, by far his lowest winning percentage against any team that he's started more than one game against in his seven years in the Majors.
Asked why the Angels have such a successful approach against him, Hernandez just shrugged.
"I don't know what kind of approach they take," he said. "Don't ask me. Ask them. They hit me pretty good."
His manager took a shot at an explanation but didn't have any great answers either.
"Sometimes it's that way," said Eric Wedge. "It's a game of adjustments, as we've said so many different times. At some point in time, whether it be an individual or a team against another team, sometimes you just don't match up well.
"Having said that, with Felix, on a particular night, I don't care who he's facing, he's just that good. They're a good-hitting ballclub, they squared up some balls, found some holes and they just kept going with it."
Hernandez faced the Angels three times over his last six starts and lost two of those with one no-decision. The Halos jumped on him out of the gate Monday, putting up three runs on four hits in the first inning, including doubles by Trout and Albert Pujols in the first three batters.
Trout added a single in the second, an RBI single in the fourth and a two-run triple in the sixth, finishing a home run shy of the cycle in a 4-for-5 night.
Mariners right fielder Casper Wells threw out Trout trying to stretch his second-inning single to a double, which turned out to be one way to get the 21-year-old who is now hitting .325 after the fifth four-hit game of his season.
"That guy is unbelievable," said Wells, who notched his team-leading seventh outfield assist. "He's having some kind of season. I was glad he did [try to stretch the single]. I thought I'd have a pretty good chance when I saw him going. I was a little surprised, but he's trying to get those extra-base hits and he's pretty fast. He takes his chances and you have to make a good throw."
Wells also homered in the bottom of the first for Seattle, his ninth of the year, as he took advantage of his increased playing time in the closing days of the season with a 2-for-5 night that included a double in the seventh.
"I feel good getting some at-bats lately and I've got a good approach now," Wells said. "My hands are up and that puts me in position to attack the baseball. I just got a good pitch I could handle and let the rest work."
Justin Smoak delivered an RBI double in the seventh in a 1-for-3 night with two walks and is 23-for-58 (.397) over his last 16 games to raise his average to .215. The Mariners added two unearned runs that frame to cut the lead to 7-4 before pinch-hitter Carlos Triunfel lined out to right with two on.
Hernandez said the one good thing coming out of his finale was that he finished the season healthy, having thrown 232 innings, his fifth straight season of 200-plus innings.
Asked to assess his season, he said: "It was fine. It was OK. I need to get better. That's it."
What exactly would The King like to improve on?
"I need to pitch better against the Angels," he said.