SEATTLE -- Jorge Polanco and Mitch Haniger ambushed Frankie Montas early, George Kirby twirled the Mariners’ fifth straight quality start and, for good measure, Jonatan Clase chipped in his first career hit and RBI on Monday night, a combination that lifted the Mariners to a much-needed, 9-3 win over the Reds on Jackie Robinson Day at T-Mobile Park.

It wasn’t just the victory, but the way it manifested that helped the club turn the page from a sour finish to the weekend -- one that ended when they spoiled run-scoring opportunities late and Julio Rodríguez was picked off to end Sunday’s game.

“Fun game,” Mariners manager Scott Servais said. “That’s what it’s supposed to be like. It’s taken us a little while to get there, but we did it tonight.”

An offense that had scored a combined two first-inning runs entering play jumped all over Montas for three runs in the opening frame. Seattle forced Montas, whom they know well from his time in Oakland, to grind through a 45-pitch inning, the most he’s thrown in a single frame, before all was said and done.

Montas walked J.P. Crawford and Rodríguez, who laid off three straight balls after falling behind 0-2. That set up Polanco, who crushed a 376-foot homer that left his bat at a scorching 109.9 mph for a three-run blast to give Kirby an early cushion.

In the third, Polanco walked again -- among the career-high-tying five for Montas -- which set the stage for Haniger, who rocketed a 398-foot blast through the marine layer and into the T-Mobile ‘Pen beyond the deepest part of left-center field.

That ended Montas’ night, after 66 pitches and just two-plus innings, at a venue where he’d thrived. Entering Monday, Montas had a career 2.05 ERA in five outings in Seattle, holding the Mariners to a .579 OPS in those games.

“I think we just have to be really committed to the heart of the plate and be aggressive and trust our eyes and have a plan up there and stick to it,” said Haniger, who also had an RBI double in the seventh. “Know what he's trying to do to you and know where you need to look to combat that. Unfortunately, the first two weeks of the season, it seems like a lot of us have been struggling. It's not just like one or two guys that are struggling.”

The Mariners had only homered twice in a home game once this year (Opening Day against Boston) and had just five homers at home entering play, the most recent being Polanco on Sunday. Seattle’s new second baseman had been off to a slow start, entering play with a .622 OPS and 33.3% strikeout rate, way above his 18.4% career rate.

“It's been really important,” Polanco said of cutting whiffs. “I’m just trying to see better pitches, trying to get better pitches, trying to swing at better pitches -- that’s kind of been my approach right now.”

Polanco’s transition to his new environment ties into the greater theme that Mariners hitters can struggle during the early weeks of any given season. It's part of recognizing that hitting in Seattle -- particularly for power -- is challenging at this time of year.

It’s been part of the club’s internal messaging since Spring Training, but it hadn’t correlated into their first 10 games in Seattle as they had an MLB-worst .272 slugging percentage at home coming into the week. However, the commentary in the pregame meeting was more pointed on Monday.

“I'm happy with how guys have come to work every day and worked hard,” Haniger said. “You don't see guys hanging their heads and sulking. It's been like, 'Alright, we're not doing well. Let's just work hard and improve and keep fighting every night.'”

The offensive outbreak offered a reminder to what the Mariners’ formula for success could look like given Kirby’s effective run suppression. After consecutive tough outings, Kirby cleared Seattle’s fifth straight quality start, surrendering just two runs on five hits, including a solo homer to Jeimer Candelario. The Mariners are 6-2 when receiving a quality start.

Moreover, he effectively expanded in deeper counts, leading to either weak contact or his six strikeouts. He even added a new grip to his slider after toying with it in a bullpen session this week.

“I thought I definitely did a better job of that,” Kirby said of expanding. “I thought there were still a couple where I should’ve gone more in or down or whatever, but it’s just a good step in the right direction, so I’m happy about that.”