SEATTLE -- Anticipating a raucous atmosphere playing in front of a sold-out crowd whose home team was on the verge of clinching its first playoff berth since 2001, A’s manager Mark Kotsay was curious as to how his young team would react.

"This place is going to be loud," Kotsay said before Friday’s contest against the Mariners. "We’ve got a lot of young players. They’ve been in some pretty good environments this year, but I think tonight might be the best one they’re gonna play in front of. We’ll see how they respond. I’m looking forward to watching it."

The response was admirable. For most of the game, the A’s played the Mariners to a stalemate by matching talented starter Logan Gilbert’s gem with their own impressive pitching performance by Ken Waldichuk and the bullpen. Ultimately, Oakland was unable to stave off a celebration in a 2-1 walk-off loss at T-Mobile Park.

Seattle got its storybook ending, punching its ticket to the postseason on Cal Raleigh’s solo homer off Domingo Acevedo with two outs and two strikes in the ninth inning. As their American League West rivals danced and dogpiled out near the pitcher’s mound, nearly every A’s player stood at the top step of the visiting dugout and watched the celebration in silence.

No team wants to watch an opponent party at its expense. But for an inexperienced A’s roster filled with rookies and young players, enduring the agony of having such festivities unfold just several feet away provides a valuable experience. It's a moment these A’s can reflect on when they find themselves on the other end of the coin.

That moment of returning to the postseason is one the A’s hope can be sooner than most think, now that top prospects such as Waldichuk and Shea Langeliers are getting their first taste of big league action. Langeliers, who was responsible for Oakland’s lone run with a booming 415-foot shot off Gilbert in the second, was among those looking inward while the Mariners celebrated.

"You watch another team experience that and you’re like, ‘That’s where I want to be,’" Langeliers said. "That’s the goal. It just motivates you even more to finish out this year strong to go into this offseason with that motivation to be where they are right now and feel the way they’re feeling. We’ll learn from it and get stronger from it."

Waldichuk did his best to try to keep the champagne in Seattle on ice for at least another night. Making just his sixth Major League start, the left-hander notched a career-high eight strikeouts as he held down the Mariners to one run over five innings.

Though Waldichuk, Oakland’s No. 2 prospect per MLB Pipeline, was displeased with his inability to pitch deep into the game due to a high pitch count, Kotsay maintained that longer outings will come with experience. Still, Waldichuk showed capable of missing plenty of bats against Seattle. His 15 whiffs (swings-and-misses) matched a career high.

Despite being heralded for a swing-and-miss fastball in the Minors, opposing batters were hitting .389 against Waldichuk’s heater in the Majors. Of the 56 four-seam fastballs he threw to Seattle, Waldichuk generated 34 swings and eight whiffs, also a new high for him.

"I felt like I figured some stuff out in my last outing that I was able to bring into this one," Waldichuk said. "In that time of traffic [on the bases], I felt like I was able to lean on those adjustments. It was a step in the right direction. Overall, better than my past outings."

Retiring 11 of his final 13 batters faced, Waldichuk, who made his Major League debut on Sept. 1, displayed the rhythm on the mound the A’s expect to be more of a common occurrence as he gains confidence at the highest level.

"The biggest thing I’ve learned is people hit mistakes up here," Waldichuk said. "Stuff that I would be able to get away with in Triple-A. I feel like I’ve been able to figure out those mistakes and figure out what the hitters are thinking. Now it’s just working on making those adjustments."

Before the game, Kotsay referred to this three-game weekend series as a barometer to see how well the A's line up against one of the league’s best. One game in, the manager remains pleased with the fight he continues to see over this final stretch of games.

"Our team played great baseball against a playoff-contending team," Kotsay said. "This is a team we’ve battled all year. Unfortunate way for us to finish the game. But it was a great baseball game. For us to stay in it and have an opportunity to win says a lot about our group."