SEATTLE -- Short-rest season came early for the Mariners on Tuesday. They had plans A, B, C, D … probably through the entire alphabet if needed, prepared to improvise with starting pitcher Tyler Anderson just two days removed from his last outing and a mostly fresh bullpen at the ready.

Behind Anderson’s wildly efficient outing, clutch run production and another booming homer from Mitch Haniger, his 38th of the season and the 100th of his career, Seattle held on for a 4-2 victory over Oakland in front of a vibrant crowd at T-Mobile Park.

Asked about his multiple contingencies postgame, Mariners manager Scott Servais raised his lineup card to the Zoom camera, a cornucopia of pastel-colored highlights illustrating the multiple outcomes in play.

He showed it off smiling, perhaps because the tactic worked masterfully.

"This is the most unique card I've ever had," Servais said. "It had all the contingencies on there. So it was a crazy night. You never know what's going to happen in the game, but you're planning for everything and as you're knocking off each inning it gets a little bit easier."

With Boston and Toronto losing earlier in the evening, the Mariners advanced to just one half-game back of the second American League Wild Card with only four games to play. They still need help in the form of the Red Sox stumbling, as they did to the 106-loss Orioles earlier in the evening, but it’s very clear at this point that the Mariners -- who have now won nine of their last 10 -- intend to take this race down to the very end.

Seattle has won 17 games this month, more than it has in any month this season. And that mark for September trails only the Blue Jays (18), Giants (19) and Cardinals (21), who won their 17th straight earlier Tuesday to claim the final National League postseason berth. Essentially, the Mariners are playing their best baseball at the most opportune time. They were last this close to a postseason spot back on May 10, when they were 18-17.

Back then, the A’s were in control of the AL West. But now, the Mariners have all but ended Oakland’s fading postseason hopes by winning their 11th straight game against their division rivals, which set a new franchise record for most consecutive wins against any single opponent, passing marks against the Royals in 1985 and the Orioles in 2000-01.

Superlatives aside, Tuesday had the feel of a postseason game. And in many ways, it was. If the Mariners are to reach the AL Wild Card Game -- in exactly one week -- they must treat every game as do-or-die, given how tight the margin is.

It began with a consultation between Servais and Anderson about short rest on Monday. The left-hander was coming off a rough nine-run, two-inning showing two days prior in Anaheim, but the Mariners were confident that the 31-year-old, who has postseason experience in two separate seasons, could quickly turn the page. And after all, he’d only thrown 54 pitches against the Angels.

Despite those liabilities, the Mariners believed Anderson was a better option than a wildly inconsistent Yusei Kikuchi, so they carefully calculated their contingencies, knowing Anderson would be on a short leash. Yet he gave them as effective of a start as he possibly could -- one run on a mistake pitch over four innings and 46 pitches, including 40 strikes.

Even though he wound up leaving with a one-run deficit, Anderson set the foundation for the Mariners’ methodical formula of winning. They just needed their bats to break through, which came via a two-run double by Jake Fraley into the right-field corner a half-inning later, an insurance run in the sixth on Tom Murphy's RBI single and Haniger’s big bomb in the seventh.

This is how the Mariners have won games all season, why they could become the first postseason team with a negative run differential since the 2007 D-backs and why they play in so many one-run games. It’s this methodical, backwards, bullpen-driven formula.

And even with a starter on short rest, it worked again. Anthony Misiewicz, Casey Sadler, Paul Sewald, Diego Castillo and Drew Steckenrider picked up Anderson and took the Mariners to the finish line, with a combined one run allowed, not even needing No. 10 prospect Matt Brash, who was called up earlier Tuesday to contribute in this postseason push.

But it all began with Anderson, who has said that he would like to return in free agency this offseason and was willing to take on the burden of short rest for his teammates of just two months. It was an all-hands-on-deck approach -- and it probably won’t be the Mariners’ last this season.