SALT LAKE CITY — Bill Self may have left a hand print on Quentin Grimes’ backside.

Grimes, the Kansas basketball freshman guard, had just committed a mental lapse on a switch during the first half of Thursday’s first-round NCAA Tournament game against Northeastern at Vivint Smart Home Arena — the fourth-seeded Jayhawks had recently changed personnel, and by the time Grimes realized his squad was running a different defensive scheme, a wide-open 3-pointer was already on its way to going in.

During a subsequent break in the action, Self lit into Grimes for the mistake. But as the guard walked to his spot on the bench, the Hall of Fame coach gave the player a forceful smack on the keister, ending the interaction on an encouraging, if not bruising, note.

Truth is, Self probably would’ve needed only that same hand to count the number of similar defensive lapses in what became a rip-roaring March Madness opener for the Jayhawks.

KU 87, Northeastern 53.

“I feel like everybody’s clicking, starting to buy in,” said Grimes, one of five Jayhawk starters who made their NCAA Tournament debut in the blowout. “Everybody knows what they need to do on the offensive end and the defensive end. I feel like we’re clicking on all cylinders right now. ...

“I would probably give (the performance) honestly like an A-minus. A-plus would be if we didn’t make some defensive mistakes. But I feel like that was honestly the most complete game we’ve played this year, just kind of not letting them come back in the second half. We just kept getting defensive stops.”

The Jayhawks saved their best for what wasn’t last, routing the No. 13-seeded Huskies in a wire-to-wire, both-sides showing. Dedric Lawson scored 25 points and hauled in 11 rebounds in just 27 minutes to pace the KU offense, and on the other end, the Jayhawks suffocated one of the postseason’s most potent long-range attacks to the tune of a 6-for-28 performance for Northeastern from 3.

The victory earned KU a second-round clash Saturday with No. 5-seeded Auburn, which survived a late collapse to defeat No. 12-seeded New Mexico State, 78-77.

“I thought we came into the game with a great mindset and performed pretty well for the most part for 40 minutes, defensively especially,” Self said. “I thought our ball screening and switching was better and it eliminated them getting a lot of uncontested looks so they could shoot the ball. It was one game, and certainly, you know, it sets up a game in which we have to be as athletic and as in tune as we’ve been all year playing Auburn.”

The Jayhawks (26-9) made hay on both ends Thursday, taking a 12-point lead into the intermission after limiting the Huskies (23-11) to just two field goal makes in the opening period’s final 10 minutes.

Northeastern, which entered the tournament with the nation’s 13th-ranked 3-point shooting percentage (38.8), hit just 5 of 17 tries from beyond the arc in the opening half, with those troubles compounded by a 1-for-9 effort on layups. Bolden Brace’s trey at the 3:52 mark off the aforementioned Grimes gaffe represented the last field goal make before the Huskies went to the locker room, the seven-point underdog enduring a 1-for-10 shooting skid before the break.

KU, meanwhile, hit just 2 of 12 tries from 3-point range but made 11 of 16 layups in the period, a far cry from the 8-for-16 showing on bunnies in the first half of the team’s eventual 78-66 defeat to Iowa State in last Saturday’s Big 12 Tournament championship game. Lawson’s 16 first-half points paced the Jayhawks, with the 6-foot-9 junior forward hitting both of the team’s 3-pointers. The second, a corner conversion with 4:06 left, capped an 11-0 run and established a 12-point lead.

Devon Dotson’s full-court driving layup — the entire sequence took about three seconds — gave KU its 37-25 edge at the break.

“I thought our guys were as locked in as they have been in a long time,” Self said. “One thing about Northeastern, it’s so important to take away shots off the catch and make them try to score off the bounce, which will be totally different with Saturday (against Auburn) because you’ve got to take away shots off the catch and be able to contain the ball so you don’t force help everywhere.

“Our guys were locked in pretty well. ... After about the 10-minute mark of the first half, I thought we executed on both ends really well.”

Northeastern took advantage of three sloppy KU turnovers in the first three minutes of the second half to cut the deficit to seven, 37-30, but that’s when Lawson and KU dropped the hammer — Grimes drilled the team’s first non-Lawson 3, Lawson followed with his third on the next trip down the court, and it was again Lawson finishing off a layup to establish a 45-30 edge with 15:25 left.

Self, who called his team “lackadaisical” during a timeout amid the rough start to the second half, called the 3s by Grimes and Lawson “probably the two biggest offensive possessions.”

“After that, we got on a good roll,” Self continued. “We moved the ball well offensively the second half.”

Dotson’s driving layup finished off the 10-0 run and establish a 17-point advantage, and by the time the Jayhawks had later staked a 55-32 advantage with 11:04 to play, Northeastern had gone just 3-for-14 from the floor and 0-for-5 from 3-point range to open the final period.

Chatting with Mitch Lightfoot from the bench during the game’s final minutes, Lawson remarked it’s been a while since KU could enjoy this kind of blowout — and the perks that accompany it.

“It’s definitely good to see everyone put in on the offensive and defensive end. It takes the pressure off us playing a lot of minutes,” Lawson said. “Everyone gets a chance to put their imprint on the game, so it’s good.”

Dotson finished with 18 points and K.J. Lawson and Ochai Agbaji each had 13 to round out the double-figure scorers for the Jayhawks, who made 6 of 10 tries from 3 in the second half to finish 8-for-22 from beyond the arc. The real damage was done inside, where a 23-for-32 mark on layups buoyed a 50-16 advantage in points in the paint.

Inside the victorious postgame locker room, Self “expressed how proud he was” of his players and their attitudes, Dedric Lawson recalled. Grimes said Self labeled the victory “a great team win.”

“We’ve got one more,” said Self, as told by Grimes. “Don’t think about the Sweet 16. Don’t think about the Final Four. Just think about the next game, the next opponent.”

“If we just do that,” Grimes observed, “I think we’ll be fine.”

There was one more notable postgame moment.

KU tasked Silvio De Sousa, the team’s ineligible sophomore forward, with putting the KU sticker on the next line on the arena’s oversized bracket — “Almost broke the board,” Lawson recalled.

It was at least the second forceful slap of the afternoon for the Jayhawks, and if the team’s leading scorer and rebounder has his way, it won’t be the last of the opening weekend.

“He put the sticker on there,” Lawson said of De Sousa, “and hopefully he’ll put the sticker on there Saturday too.”

KANSAS 87, NORTHEASTERN 53

NORTHEASTERN (23-11)

Green 1-2 3-6 5, Roland 5-13 0-0 12, Pusica 2-13 1-2 7, Gresham 2-8 3-4 7, Brace 1-5 4-4 7, Strong 0-1 0-0 0, Miller 2-3 0-0 4, Murphy 1-5 0-0 3, Franklin 0-1 2-2 2, Occeus 2-6 2-2 6. Totals 16-57 15-20 53.

KANSAS (26-9)

D.Lawson 9-16 4-4 25, McCormack 0-0 0-0 0, Agbaji 5-5 2-2 13, Dotson 6-12 5-5 18, Grimes 1-6 0-0 3, Lightfoot 2-2 0-0 5, K.Lawson 6-10 0-1 13, Moore 1-4 0-0 2, Luinstra 0-0 0-0 0, Teahan 0-0 0-0 0, Garrett 4-6 0-0 8. Totals 34-61 11-12 87.

Halftime — Kansas 37-25. 3-Point Goals — Northeastern 6-28 (Pusica 2-6, Roland 2-8, Murphy 1-2, Brace 1-3, Miller 0-1, Occeus 0-3, Gresham 0-5), Kansas 8-22 (D.Lawson 3-5, Lightfoot 1-1, Agbaji 1-1, K.Lawson 1-3, Dotson 1-5, Grimes 1-5, Moore 0-2). Fouled Out — None. Rebounds — Northeastern 24 (Brace 9), Kansas 42 (D.Lawson 11). Assists — Northeastern 7 (Brace 4), Kansas 12 (Grimes 3). Total Fouls — Northeastern 12, Kansas 19.