MINNEAPOLIS - Seattle's late-summer surge has been fueled, naturally, by strong starting pitching.

Even the offense has been perking up. After so many rough seasons, August has been a pleasant month for these Mariners.

Dustin Ackley hit a three-run homer, Hisashi Iwakuma was hard to hit and the Mariners beat the stumbling Minnesota Twins 5-2 on Tuesday night.

"Ever since the All-Star break I feel like we've been hitting more consistently," Ackley said. "We've had a couple games where we might not have scored as many as we like, but overall I feel like our hitting has been great."

Iwakuma (5-3) gave up one hit and one unearned run over six innings in another strong start for the rookie from Japan. The right-hander struck out four and helped send the Twins to their 16th defeat in their last 19 games despite four walks, a hit batsman and a wild pitch.

"He did it the hard way," manager Eric Wedge said. "He was erratic. Didn't quite have the same command that he normally does, but he didn't give into it."

Ackley hit a fastball from Scott Diamond (10-6) into the flower bed above right-center field following consecutive singles by Trayvon Robinson and Brendan Ryan to start the fifth.

"I just left it right in his bat path," said Diamond, who gave up more than three runs for the first time in seven starts since July 21.

After Ryan Doumit's RBI double off Charlie Furbush, Tom Wilhelmsen got the last out of the ninth inning for his 20th save in 23 attempts. The announced attendance was 29,854, the first sub-30,000 crowd to watch the Twins since Target Field opened in 2010.

The Mariners, who began the day nine games behind in the AL wild-card race, have won 12 of their last 16. They have won seven straight against the Twins and raised their record to 63-67.

"I think after we had a couple of those winning streaks and started hitting real well I think it was in everybody's mind," Ackley said of reaching the .500 mark. "I think the more we won the more we believed that we could do that."

Iwakuma is 4-1 with a 1.99 ERA in his last eight starts. Mariners starters, buoyed by ace Felix Hernandez, who spun a five-hit shutout Monday, are 19-8 with a 2.74 ERA in the last 37 games. Since the All-Star break they have the second-best ERA in the majors.

"Pitching, I don't think that's ever been a problem here," Ackley said.

But hitting has been. The Mariners remain on pace to finish in the bottom five in the majors in runs scored for a fifth straight season. Lately, there has been improvement.

Diamond gave up a double to Ryan and walked Franklin Gutierrez with two outs in the third before Kyle Seager's two-run double put the Mariners on the board. Seager leads the majors with 43 two-out RBIs.

Ryan had three hits, matching his season high, and raised his batting average to .202.

"He's at his best when he's aggressive and lets the bat go," Wedge said, adding: "When he just relaxes and let's it go out there and just hits, he's got a good swing."

With his unorthodox, halting windup and the exaggerated kick of his right leg before he releases the ball, Iwakuma had the Twins off balance all game. He allowed a run before he surrendered a hit, when consecutive walks set up Ben Revere for a sacrifice fly in the third. Not until one out into the fifth did the Twins get a hit, a single by Jamey Carroll.

Iwakuma, who joined the rotation on July 2, said through his interpreter he struggled to feel comfortable on the mound.

"I tried to fight it by myself. The most I could do was not give up any runs," he said.

Carroll called him "effectively wild." The Twins finished with four hits.

"You've got to tip your hat to him, I guess," Twins manager Ron Gardenhire said. "He made the pitches when he had to. Even when we got into hitting counts, we didn't do anything with it."