SEATTLE — On a night when the Yankees punched their ticket to the postseason, Nestor Cortes continued to make his case to be a part of their playoff rotation.

The left-hander delivered six shutout innings against the Mariners on the way to a 2-1, 10-inning win on Wednesday night at T-Mobile Park.

“I’m just trying to pull my weight around here and compete with the guys that are the best around the league,” Cortes said amidst a rowdy champagne and beer celebration inside the visiting clubhouse.

Cortes has now pitched to a 1.58 ERA over his last six outings — one of which was a long relief appearance as the Yankees put him in the bullpen one turn through the rotation.

Though Cortes has past experience out of the bullpen and could help the Yankees there in October, he also has previously started playoff games and has shown he is not intimidated by the big stage.

“Nestor’s done a fantastic job for us this year,” Gerrit Cole said. “He’s taken the ball every single time in whatever role we’ve asked him. He’s pitched well and gave us a chance to win almost every time he goes out there.”

Marcus Stroman is currently the odd man out in the bullpen this turn through the rotation, but the Yankees will have to trim another starter or two once they get to the playoffs.

Wednesday’s outing was Cortes’ fourth scoreless appearance in his last seven games.

He limited the Mariners to four hits (one of them a double by Justin Turner that Jasson Dominguez should have caught in center field) and three walks while striking out six.

“I feel like he’s throwing the ball really well,” manager Aaron Boone said. “Feel like it’s been a real strong year for Nestor.”

For the first time this season — aside from when he missed five weeks with a hamstring strain — Giancarlo Stanton was out of the lineup Wednesday for a second straight game.

Stanton said he was fine physically, but he was on the bench for a second straight day as Aaron Judge received another DH day to help keep him fresh down the stretch.

“We’re not going to make this a story of how I feel [about not playing],” Stanton said before the game. “We’ll be fine either way.”

Stanton described being out of Tuesday’s lineup as matchup-based against tough right-hander Bryan Woo.

Then he was not going to play both Wednesday and Thursday (with Thursday being a day game after a night game), and the Yankees decided Thursday (against right-hander Logan Gilbert) was a better day for him to be in the lineup.

The consecutive days off may have more to do with Boone wanting to get Judge off his feet again at this point in the season after playing a demanding center field regularly.

“Judgey’s good, but I certainly value those days for him at this time of the year, especially coming out of an off day [Monday],” Boone said. “Obviously as much as we’ve leaned on him and others, I want to be mindful of that this time of year.”

Boone indicated that Stanton — who was 4-for-34 with two doubles over his last 10 games — would be back in the lineup consistently the rest of the way.

After Clay Holmes gave up a game-tying home run to Justin Turner in the eighth inning, Luke Weaver entered and struck out four across 1 ²/₃ ⅔ innings to send the game to extras. … The Yankees struck out a season-high 15 times.