SEATTLE -- Some early-game adversity Monday night tested Mariners right-hander Doug Fister like never before this season.

The way he responded was impressive, but it still could not prevent another Mariners loss in May -- this one a 5-4 setback to the Twins in front of 19,795 at Safeco Field.

And so, a month that started with six consecutive losses, ended with the Mariners on a three-game skid. Seattle (19-31) went 8-19 during the second month of the season, limping into June eight games behind in the American League West.

But you can't blame Fister for the rough month.

He had four quality starts and went into the series opener against the Twins leading the AL in ERA.

Fister is now second to Tampa Bay's Jeff Niemann, but that was secondary to how he handled the Twins' offense after surrendering five runs in the first four innings -- the first time in 10 starts this season he allowed more than three runs in a game.

But Fister regrouped and retired 11 of the last 12 batters he faced. The one batter that reached base -- Denard Span on a leadoff single in the eighth inning -- was erased on a double play.

Fister's bend-but-don't-break outing gave the Mariners a chance for their own walk-off victory in the ninth inning. But after Jose Lopez doubled and scored on Josh Wilson's single up the middle, Twins closer Jon Rauch got three outs on two pitches -- one apiece to pinch-hitters Ken Griffey Jr. and Casey Kotchman, whose bid for a game-tying extra-base hit to right field turned into a game-ending double play.

"The ball Casey hit unfortunately was right at [first baseman Justin] Morneau," Wilson said. "Otherwise that scores a run. I guess you could say that's typical of what has been happening [in May], but at the same time, we still believe things are going to start changing.

"Those walk-off wins will start going the other way. Those balls will start getting through."

And not a moment too soon for a team that has now lost 13 games by one run.

"I know it doesn't mean a whole lot in the win column," manager Don Wakamatsu said, "but watching our club play tonight, you couldn't tell we just got walked-off two days in Anaheim. They came out and battled, down, 5-1, against a first-place club, and battled all the way back."

Fister did his part by not falling apart after surrendering back-to-back home runs to Michael Cuddyer and Jason Kubel on consecutive pitches in the fourth inning. After Delmon Young, who hit a two-run home run in the second inning, doubled, Fister avoided further damage when center fielder Franklin Gutierrez made a diving catch for the final out of the inning.

It was the first of 10 consecutive batters Fister retired before departing in the eighth.

"The nice thing about it is that the whole outing could have gone a different way, but he kept us in the ballgame," Wakamatsu said. "I thought he competed all night. You look at that outing and there were three balls he got up in the zone and got hurt on. But he knew our bullpen was short, and he continued to battle, giving us 7 2/3 innings when we didn't have anybody in the bullpen."

Fister didn't have his best stuff, topping out at 91 mph, but he made a fourth-inning adjustment that allowed him to keep the ball down and set a season high in strikeouts with six, four of them on called third strikes.

He also set a season high in home runs allowed -- three.

"They have a great lineup," Fister said. "I made couple of mistakes, and really that's what hurt me, just getting the ball up. I was trying to go in a couple of times and the two-seamer ran back across the plate too much."

The three home runs Fister surrendered equaled the most in one game during his 19-game MLB career. He had allowed just two this season.

"He made a lot of good pitches," Wilson said. "Unfortunately, it was just the ones he didn't make he got hurt on. He held pretty good hitters off the board. I guess this was not his best outing overall, but we were still in that game and had a chance to win.

"Doug is ice cold out there on the mound. He never shows any fear. He gives up a home run and comes back with a strike, gives up a home run on the next pitch and comes back with a strike. That's the way he is. He's not going to give in.

"He's mature beyond his years, for sure."

Fister is now 3-3 with a 2.45 ERA, still among the league leaders. He leads the league with eight starts of seven-plus innings.

"He's got great stuff," Twins manager Ron Gardenhire said. "I think you can see that. He's got a great changeup, a heck of a curveball and a nice little slider. He is tough.

"He made some mistakes and we got a hold of them pretty good," Gardenhire added.