CLEVELAND — Luis Severino removed any lingering doubt about it, if there even was any, Sunday afternoon.

If the Yankees make the postseason, Severino will start the first playoff game, whether it be the wild-card game or Game 1 of a Division Series.

The 23-year-old blitzed through a tough Indians lineup, allowing two hits and striking out nine in 6 2⁄3 innings in an 8-1 victory in front of 33,044 at Progressive Field.

Said catcher Austin Romine, “It was pretty dominant.”

The Yankees (59-51) had 12 hits, including a three-run triple by Jacoby Ellsbury and a three-run homer by Aaron Judge. They earned a split of the four-game series against the AL Central-leading Indians (59-50) and remained three games behind the AL East-leading Red Sox.

“We just split with a really, really good team,” said Joe Girardi, whose club lost the first two games of the series after dropping the final two games of their series against the Tigers. “You go 2-2 against Cleveland, it’s a pretty good series.”

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After managing only three hits through five innings against Carlos Carrasco (10-5) and falling behind 1-0, the Yankees scored eight runs in the next two innings. Ellsbury lined a bases-loaded triple and scored on Ronald Torreyes’ single to cap the Yankees’ five-run sixth. Judge’s 35th homer, a line-drive laser to right-center off Mike Clevinger in the seventh, made it 8-1.

“With Sevy, you get one or two runs,” Judge said, “you’re set for the game.”

Offensive outburst aside, the story of the afternoon was Severino, who improved to 9-4 with a 2.91 ERA. Entering the seventh, the only hit off the righthander — who was 3-0 with a 0.69 ERA in his previous four starts — was a two-out homer by Michael Brantley in the first inning. He walked one and, in his own way, looked as dominant as Indians ace Corey Kluber, a Cy Young Award candidate who shut down the Yankees on Thursday night.

“Corey Kluber was as special as it gets,” Girardi said. “But I look at Sevy, he gave up two hits in 6 2/3 innings, he pitched really, really well. And Sevy’s stuff just doesn’t fall off.”

After Brantley’s homer, Severino struck out five of the next seven he faced, giving him seven strikeouts through three innings.

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The Yankees, who had scored five runs and struck out 46 times in their previous four games and fanned 10 more times Sunday, didn’t get their first hit until Didi Gregorius slapped a 1-and-2 slider back up the middle with two outs in the fourth.

With no margin for error, Severino pitched out of a jam in the bottom half. Francisco Lindor walked, went to second on a wild pitch and moved to third on Brantley’s grounder to short. But Severino got Jose Ramirez to foul out to third and Edwin Encarnacion to line out to right to keep the score 1-0.

“We won, that’s the bottom line,” Severino said. “Every time they give me the ball, I’m going to give 100 percent. I think all my pitches were there, my changeup was there, my fastball was good.”

The Yankees finally broke through in the sixth. Brett Gardner led off with a single and Clint Frazier pulled a 2-and-2 slider down the third-base line for a double. After Gregorius popped to third, Carrasco fell behind Judge 2-and-0, and although Judge already had struck out twice, Indians manager Terry Francona ordered him to be intentionally walked to load the bases.

Chase Headley, whose eighth-inning homer gave the Yankees a 2-1 victory Saturday night, skied one to center for a sacrifice fly that made it 1-1. Todd Frazier drew a walk to re-load the bases and set up Ellsbury, who swung at a first-pitch fastball and drove it over rightfielder Abraham Almonte’s head for his second triple of the season and a 4-1 lead.

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Almonte might have been able to go back a little farther and appeared to mis-time his leap for the ball, which hit the base of the wall. “A ball that should have been caught,” he told reporters afterward.

As Judge said, the runs were more than enough for Severino.

“I think we see it, I think everybody sees it,” Romine said. “He’s on the corners, he’s throwing 100 for the whole game and he’s got two different kinds of sliders. When you have 100 coming at you and you throw a lot of sliders, it’s going to be hard to hit.”