After jumping out to an 8-2 lead in the first three minutes, the Massachusetts men’s basketball team crumbled in all facets against Dayton en route to a 72-48 loss.

UMass (10-18, 3-12 Atlantic 10) started off well, jumping out to a six-point lead and getting stops on four of the first five offensive possessions for Dayton (19-9, 11-4 A-10). But the Flyers cut the lead to one right before the first media timeout and UMass went on to allow a 38-10 run over the final 17 minutes of the first half, as the Flyers shot 86.7 percent in that dominant stretch to more or less decide the game by halftime.

We didn’t bring it, we didn’t play hard, we didn’t compete,” McCall said. “We acted like we didn’t want to be there, and that’s about as blunt and blatantly honest as I can be.”

The Minutemen fell apart across the court, but particularly defensively, where Dayton got open look after open look under the basket. Obi Toppin was the primary beneficiary, as he scorched the Minutemen in the paint for 19 points and threw down six dunks. 40 of Dayton’s 72 points came in the paint.

“It was a layup drill for them,” coach Matt McCall said. “There was no resistance at the basket. That’s all we talked about yesterday, having resistance at the basket, protecting the white line. They run the same stuff we do. So we’ve been guarding this stuff since July, and our white line protection was awful, our pick-and-roll coverage was bad. They had us spinning around defensively.”

Inside, the Minutemen were boxed out for much of the game, but 15 rebounds in the final 12 minutes compared to just six for Dayton made the final numbers more respectable. Walk-on center Randall West pulled down six rebounds in his nine minutes late in the second half to lead UMass.

“He got six in nine minutes,” McCall said. “He has no clue what he’s doing on offense, zero. But he can impact the game because of how hard he plays. And you know what, he’s genuinely upset in that locker room that we lost.”

After that truly abysmal first half, in which UMass gave up 40 points and scored just 18 on 31 percent shooting, the Minutemen looked better in the second when Dayton took its foot off the gas. UMass shot 39 percent from the field, but never closed to within 20 as the Flyers cruised.

“[The Flyers] aren’t worried about their numbers,” McCall said. “We’ll shoot shots when it’s late in the game, when the game’s out of hand, but there’s a loose ball late in the game and we won’t dive on the floor. I heard a fan say, ‘Make a hustle play!’ Yeah, I agree with them.”

UMass went into the game shorthanded, losing two key players within 24 hours of tip-off. Freshman Samba Diallo, arguably the best defender of the Minutemen, took a seat with a knee problem, while center Rashaan Holloway missed the game with an eye infection. Those two joined Luwane Pipkins, who has been battling a hamstring injury for the better part of a month.

But those three would hardly have compensated for a lackluster defense that allowed Dayton to score at will, which caused McCall to once again question the motivation of his team.

“It’s February 26, and we have a guy late for shootaround,” McCall said. “On February 26. In the middle of a grind, we’re battling, we’re fighting for every single day, every single game, every single possession, and you can’t get to a 2 p.m. shootaround on time? How can we expect to go out there and play and compete and focus and do our job? I’m calling plays that we’ve run since July, and we forget the action. We’ve been running it since July. That’s a lack of focus.”

UMass has five days off to refocus before going on the road to face Duquesne.

Thomas Haines can be reached at [email protected] and followed on Twitter @thainessports.