MINNEAPOLIS -- It didn't click for Nickeil Alexander-Walker right away.

Earlier Friday morning, Minnesota Timberwolves coaches and players were telling him to "just be ready" for that night's play-in matchup against the Oklahoma City Thunder. Alexander-Walker thought it was just normal pre-game talk.

He knew his matchup would be against a familiar opponent -- his cousin Shai Gilgeous-Alexander -- he just didn't realize what that would mean: He was starting.

"This morning at shootaround, there's my name on the clip with the matchups and I finally put it together," Alexander-Walker said.

In a repeat of a matchup that happened countless times for the two growing up, it was Alexander-Walker who got the better of his cousin Friday night and helped lead the Timberwolves to a decisive 120-95 victory that gave them the No. 8 seed in the Western Conference playoffs.

Alexander-Walker helped hold Gilgeous-Alexander to 5-of-19 shooting (26.3%) from the field, a season-low. When asked about Alexander-Walker's performance, Karl-Anthony Towns didn't hesitate.

"X-factor," Towns said. "He's the reason we won. He went out there and had a very, very tough job tonight to guard Shai, who's been fantastic this whole year and one of the best scorers in the league. And to go out there and do what he did is the reason we won. There's no other way to put it."

Once it settled in that he was getting his first start of the season for the Timberwolves, Alexander-Walker said he tried to take a step back.

"I was just so thankful for that opportunity to start and then have that assignment to guard him," Alexander-Walker said. "It's a little different than any other game. This is someone I grew up with my whole life. As far as people, he knows me better than anybody and he knows me better than anybody I could say."

The cousins, both 24 years old, were born just 52 days apart -- Gilgeous-Alexander is older -- but had not squared off much on the NBA level. In fact, entering Friday night, Alexander-Walker had guarded his cousin in only 27 half-court matchups during his four NBA seasons and held him to 3-of-11 shooting.

On Friday night, Alexander-Walker matched up against him 41 times. The results? Gilgeous-Alexander scored just eight points, went 3-of-12 from the floor and drew just two free throws against Alexander-Walker. Against all other Timberwolves, he was 2-of-7 but drew 10 free throw attempts, making all 10.

They had played against each other all their lives, but this was on a win-or-go-home stage. The two spoke before the game and embraced each other once the final buzzer sounded.

Timberwolves coach Chris Finch said the idea to start Alexander-Walker on Gilgeous-Alexander actually came from the front office.

"Quite honestly, it was something that [Timberwolves president of basketball operations] Tim Connelly said, 'Hey, here's a wild one, what do you think?' and I was like, 'It makes a lot of sense,'" Finch said.

The Timberwolves entered the matchup without defensive stalwart Jaden McDaniels who broke his right hand Sunday after punching a wall in the tunnel. Without McDaniels, turning to the 6-foot-6 Alexander-Walker was the move.

When Alexander-Walker was drafted to the New Orleans Pelicans in 2019, Finch was an assistant coach on the team, so he has had a chance to watch Alexander-Walker grow throughout the years.

"I mean, I thought like most young players when we had him as a rookie he was a defensive liability," Finch said. "The game was moving fast. He was trying to catch up. But he's really added defensive intelligence and competitiveness to his game. And that's really gonna carry him a long way because he's a smart player."

While Alexander-Walker led things at the point of attack, the rest of the Timberwolves' defense thrived as well, holding the Thunder to 36.0% shooting overall and just 95 points.

On the other end of the floor, the offense clicked in a way it hadn't against the Lakers in the first play-in game Tuesday.

Towns (28 points, 11 rebounds), Anthony Edwards (19 points, 10 rebounds) and Rudy Gobert (21 points, 10 rebounds) all finished with double-doubles.

Gobert was questionable coming into the game with back spasms, and the result was much different than his last home game Sunday when he got into a verbal altercation with Kyle Anderson and threw a punch at him in a Timberwolves huddle. Minnesota held Gobert out of that game and suspended him for the Lakers game.

The back was an issue, and Gobert said he knew it was affecting him Sunday. He said he thought it was going to be tough playing Friday night before an MRI showed there wasn't any major damage.

With 7:52 left in the fourth quarter, Gobert put questions about his back aside.

Mike Conley controlled the loose ball on one end of the court, stopping a fast break in the process. He turned and fired the ball 80 feet up the court to an awaiting Towns, who immediately caught the pass and fired it toward the rim, where Gobert was waiting.

As Gobert caught the ball and flushed home the slam, the announced crowd of 19,304 inside the Target Center erupted as it became clear -- the Minnesota Timberwolves were headed back to the playoffs for back-to-back seasons for the first time since going to eight straight from 1996 to 2004.

And they'll match up against a top-seeded Denver Nuggets squad that didn't see them at all this year when Towns was healthy.

"To be honest, I don't consider ourselves as an 8-seed," Gobert said. "We are in the standings, but I don't consider us an 8-seed. Now, it's an amazing opportunity for us to keep getting better as a team. It's a huge challenge for us. It's an exciting opportunity.

"But we're not looking at the standings anymore. We're looking at who is in front of us. We believe if we play the right way, there's not a team in this league that we cannot beat."