Waiting for Justin Smoak to show off his batting power has become a seasonlong preoccupation for a Mariners team needing offense on nights like these.

And power was something that came in handy for the Mariners in a game that saw both teams pile up the hits but struggle to push runs across. Smoak took care of that issue on one swing with a tying solo home run in the seventh inning, then watched John Jaso deliver a bases-loaded sacrifice fly in the ninth for a 3-2 walkoff win over the visiting Minnesota Twins.

This fourth consecutive win by the Mariners, in front of 21,154 fans at Safeco Field, saw Smoak deliver multiple extra-base hits for only the second time all season. The only time he'd managed that feat before came at Texas back on May 30 in a 21-8 rout by Seattle in which he hit two home runs and also doubled.

"I've been here the majority of the year, but it's just a matter of having confidence up there," said Smoak, who also doubled in the fifth inning. "I feel like I'm there right now. I've just got to stick with what I've been doing and stay confident from there."

The Mariners pushed the winning run across in the ninth after Michael Saunders had opened the inning with a single off relief pitcher Tyler Robertson.

Brendan Ryan tried to bunt Saunders to second and first baseman Justin Morneau was a little too casual in picking the ball up. Morneau threw late to first, everybody was safe, and then a walk to Dustin Ackley loaded the bases with no outs.

"That was a gift," Ryan said of Morneau's botch, the second time this homestand an opposing player has mishandled a bunt in the ninth.

The Twins brought Casey Fien in to face pinch-hitter Jaso, who worked the count full, then drove a ball to left field. Saunders easily beat the throw and the Mariners had their 11th win at home in the last 12 tries.

"It's nice to win a close game," Ryan said. "As a young team, we should be learning how to win these games."

Minnesota had a chance to take the lead in the top of the ninth, loading the bases with two outs on a single and two walks. But Mariners closer Tom Wilhelmsen came on and got the dangerous Josh Willingham to fly out to right field to end the frame.

"I knew he was going to come in hacking," Wilhelmsen said. "They were — even yesterday, he was looking for a fastball, swinging on a fastball. So, I figured I'd start him off with a curveball and sure enough, he hacked. Both pitches. Just got under that fastball a bit and it was enough to get the third out."

Jason Vargas was coming off another strong outing against the Angels in Anaheim, Calif., and had an extra day's rest. He wasn't overpowering, striking out only two batters over 6-2/3 innings of work, but overcame some early problems and was tied 1-1 heading into the seventh.

"I was trying to limit the damage and just keep making pitches," Vargas said. "You control the damage, know where you're at, don't let the game speed up and try to keep your team in the game."

But Vargas saw three of the first four hitters line singles to left field in the seventh to load the bases with one out. Joe Mauer then grounded into a fielder's choice in which the Mariners got the out at second but couldn't complete the double play, allowing the go-ahead run to score.

Vargas exited at that point, his pitch count at 113. Josh Kinney came on and ended the inning with a ground out.

Smoak quickly tied it up in the bottom of the inning, getting all of a full count offering from Twins starter Scott Diamond and putting the ball over the wall in left center. The solo homer was the first long ball for Smoak since July 17 in Kansas City, a monthlong drought that saw him dispatched to Class AAA to work on his swing.

The last game in which Smoak had multiple extra-base hits also helped him clinch honors as the American League's Player of the Week. Smoak said that the confidence he's feeling now is similar to what he felt then.

"That's the confidence you need to have day-in and day-out, and that's something I've learned," Smoak said. "You struggle and you try to learn from it. That's something I think I've learned from. No matter what happens out there, you've got to stay positive, and that's where I'm at right now."

Mariners manager Eric Wedge said it helped to have a game-changing swing by Smoak on a night his team hit the ball hard but had little to show for it on the scoreboard.

"That's the ability he has, that's the impact he can have from both sides of the plate," Wedge said. "He's obviously had better AB's since he's been back here."

Geoff Baker: 206-464-8286 or gbaker@seattletimes.com.