SEATTLE — In the end, when they needed a big hit, it was Josh Naylor, the man who brought such a noticeable edge to this surging Seattle Mariners team over these past two months, who delivered it.

His eighth-inning, bases-loaded three-run double Tuesday night triggered a 4-3, come-from-behind victory over the Colorado Rockies, sent the Mariners back into the postseason and put them on the cusp of a long-awaited division title. The last time the Mariners won the American League West, it was 2001, a year highlighted by 116 regular-season wins. That can change as early as Wednesday, with either another win by them or another loss by the Houston Astros.

But first, the Mariners celebrated their first postseason clinch since 2022 — and hoped for many more.

“We wanna do all of ’em — and a big one in the end,” Naylor said, puffing on a cigar just steps away from a champagne-and-beer celebration in the middle of the Mariners’ clubhouse. “With a nice parade around the city.”

Seattle remains the only current major league city that has yet to host a World Series game, but this season’s team is continually inspiring hope for October.

Tuesday’s win was the Mariners’ fifth in a row and 15th in a stretch of 16 games — immediately following a 6-15 stretch that made fans wonder if their team was poised for another late-season slide. It followed a resounding sweep in Houston, one in which the Mariners never trailed. And it has them thinking their best might be ahead of them.

The Mariners’ vaunted rotation — minus Bryan Woo, nursing a pectoral injury the team hopes won’t keep him out of the playoffs — is dominating again as so many expected at the start of the season. Their lineup, bolstered by the midseason additions of Naylor and fellow corner infielder Eugenio Suarez, is producing. Their bullpen looks lethal. In a year when practically every team possesses glaring weaknesses and has navigated tough stretches, the Mariners are making a case for being the most complete.

“There is a lot of work to do, starting with the division,” said Dan Wilson, a longtime Mariners catcher in his first full season as their manager. “Hopefully we get that done sooner than later and we keep going. But there’s a lot ahead of us. And this team I think is ready and primed for it.”

The Mariners won 90 games and snuck into the playoffs, ending a 21-year drought, in 2022. They followed by winning back-to-back games in Toronto during the wild-card round but lost three consecutive heart-wrenching ones to the Astros in the division series, the last one an 18-inning shutout. In 2023, they flamed out in September and were eliminated on the penultimate day of the regular season. In 2024, they blew a 10-game lead in the division and were eliminated with three games left.

“These last two years have felt really long,” Mariners catcher Cal Raleigh said. “Not going back, it’s been hurtful. A lot of pain.”

That struggle, some of the players believe, helped produce this moment.

“Those years served its purpose — to get us stronger,” Mariners center fielder Julio Rodriguez said. “To get us in a better position. To grow.”

Raleigh at one point put his arm around Jerry Dipoto, Mariners president of baseball operations, lamented how they had just played eight innings of bad baseball, then shifted the focus. “Let’s go win the World Series,” Raleigh recalled saying.

For seven innings, the Mariners’ offense lagged against a Rockies pitching staff that possesses the highest ERA in the major leagues. They trailed 3-1 heading into the bottom of the eighth, but Rockies reliever Juan Mejia started the inning by plunking Luke Raley. J.P. Crawford followed with a walk, but Randy Arozarena and Raleigh struck out. Rodriguez then took a 1-2, 97.5 mph fastball off his left elbow guard, to load the bases.

Three pitches later, Naylor — slashing .292/.333/.486 since being acquired from the Arizona Diamondbacks on July 24, seven days before Suarez also came over from the D-backs — sent a 2-0 fastball into the left-center-field gap, scoring Rodriguez from first base.

“It felt like two seconds,” Rodriguez said. “It felt like two seconds for me, honestly. As soon as I saw him hit the ball in the gap, I just started running.”

Andres Munoz, the Mariners’ lights-out closer, breezed through the ninth, sending a T-Mobile Park crowd of 35,925 into jubilation. The Mariners improved to 49-27 at home. Their lead over the Astros has stretched to four games with five left. Their lead over the surging Cleveland Guardians and Detroit Tigers, suddenly tied in the AL Central, is at three games for a first-round bye.

It has been nearly a quarter century since the Mariners won a playoff game at home.

They want as many as they can get this year.

“We want to play at home,” Rodriguez said. “I don’t want to leave my neighborhood to play.”