INDIANAPOLIS – Center Stephanie Mavunga tried her best to describe Ohio State’s improbable comeback during a Big Ten tournament semifinal in which the team seemed to be trying to fit square pegs into round holes.

“It’s March, so the madness has begun,’’ she said.

Behind seniors Mavunga and guard Kelsey Mitchell, the Buckeyes counter-punched past Minnesota in the final minutes to win 90-88 on Saturday night at Bankers Life Fieldhouse.

Video: Ohio State guard Kelsey Mitchell

Ohio State (26-6) won the regular-season championship outright, but Mitchell said the players want their first conference tournament title since 2011 going against teams hungry to knock them out.

“It’s winning,’’ she said. “You’re talking about championships, you’re talking about trophies, you’re talking about going home with hardware for your team.’’

The Buckeyes will face No. 17 Maryland, which beat Nebraska 66-53, in the final Sunday.

The semifinal was not suitable for framing, with Ohio State giving up 16 points off turnovers and missing 14 of 28 free throws, including nine of their first 10 in the second half.

The Buckeyes did play a second straight game without versatile senior guard Asia Doss because of a sprained right ankle.

It was a good thing Mavunga, the Indiana native from nearby Brownsburg, and Mitchell brought their A games.

“Stephanie was relentless, absolutely incredible,’’ coach Kevin McGuff said.

Mavunga had 26 points, a conference tournament-record 21 rebounds and seven blocked shots. It was the first time at the Big Ten women’s tournament that a player topped 20 points and 20 rebounds in a game.

“I just tried to get every single rebound that was out there offensively and defensively,’’ she said. “My team did a really good job of patting me on the back and getting me riled up down the stretch. I felt I let my team down (earlier). Kelsey did a good job of calming me down. She said, ‘Steph, get the next play.’’

Mitchell put up 30 points, four rebounds, nine assists and two blocked shots in playing 40 minutes.

Things looked bleak for the Buckeyes after Gophers guard Kenisha Bell drove the length of the floor for a layup to make it 85-79 with 4:40 left.

The comeback started when guard Linnae Harper hit a short jumper in the lane and Mitchell a three-point play on a running bank shot from 10 feet to cut the gap to 85-84 with 3:17 left.

“I saw an open shot and tried to take it,’’ Mitchell said. “Coach called a certain play for the team and I saw a lane and took it. I tried to stay in the moment.’’

Ohio State took the lead for good 86-85 on a short bank shot by forward Alexa Hart with 2:39 left. Two free throws by Mitchell made it 88-85 with 29.3 seconds left.

Mavunga came up with the defensive play of the game when she got a hand on a three-point attempt by guard Carlie Wagner with 20 seconds left. Hart rebounded, was fouled and made one of two free throws for an 89-85 lead.

“I was looking not to foul — everyone was stressing don’t foul, don’t foul, especially a jump shooter,’’’ she said. “I knew Carlie was going to shoot then and I just wanted to get my hands on the ball — anything to keep her from scoring.’’

Minnesota was 3 of 17 from the field in the fourth quarter.

“I was really proud of the way we played at the end,’’ McGuff said. “We executed our defense really well.’’