"A great performance by Felix," Mariners manager Eric Wedge said. "Just really commanded the ballgame throughout.
"It's a tough lineup, but you have to execute pitches. Every pitch has to have a purpose, and Felix understands that more than anybody and just did a great job tonight -- really proud of his performance, really stepped up for us."
It is the fifth time in 10 starts this season that Hernandez has lasted eight innings and the eighth time he has struck out at least six.
It was Hernandez's first victory over the Rangers since the end of the 2010 season. He was 0-4 with a 5.04 ERA against them last season.
"He had a good changeup and made pitches when we were about to put up runs," Rangers manager Ron Washington said. "We've seen it before, he's capable of doing that. Tonight was his night and wasn't Darvish's."
The Mariners were patient at the plate, earning six walks from Darvish in his four innings, making the righty throw 96 pitches before he exited. Darvish is 1-1 with an 8.38 ERA with 10 walks and 10 strikeouts against the Mariners in two starts this season, compared with his 1.94 ERA against the rest of the league.
"I think the last time he was known to maybe be a little wild, so I think we were just patient, just looking for our pitch," said Mariners leadoff hitter Dustin Ackley, who had a hit, walk and run. "The counts, it wasn't like they were all 3-0, they were 3-2, 3-1 walks, so it seemed like we were seeing the ball pretty well tonight."
The Mariners' patience early yielded good results, as Michael Saunders drew a four-pitch walk in the first and scored on an Ichiro Suzuki triple.
Ichiro again came through for the Mariners in the third. With runners at first and second, he flared a single into shallow left-center to score Ackley from second. Josh Hamilton tried to throw out Saunders at third but sailed the ball into the Rangers dugout.
The throwing error scored Saunders and advanced Ichiro, who scored two batters later on a sacrifice fly by Jesus Montero to increase the Seattle lead to 4-0.
Darvish escaped big trouble in the fourth when he walked the bases loaded to begin the frame. But all the Mariners were able to plate was a single run, as Darvish escaped the jam with a pair of fielder's choices and a strikeout.
But with Hernandez on the mound and an early lead, the Mariners didn't need to put much more in the run column.
"We're so confident when he's up there, especially when we get runs early for him, we're like, 'We're in the driver's seat right now,'" Ackley said. "I think that allows us to hit a lot better and be more comfortable. When you get four or five runs for him early, you're like, 'OK, we're right where we need to be.'"