LOWELL — Three seconds of lost focus, two points vanished and one frustrated UMass hockey team.

That was the simple math Friday night for the No. 8 Minutemen. A dominant effort against No. 14 UMass-Lowell went to waste in the blink of an eye in an arena that has become a house of horrors for UMass.

The River Hawks scored twice in the third period to beat UMass, 3-2, and extend the Minutemen’s woes to 12 straight defeats at the Tsongas Center.

“We just come off the page for a little bit and that’s it, it’s in your net,” sophomore Bobby Trivigno said. “It’s just really disappointing. We outplayed that team for two and a half periods then we have a mental lapse where we’re weak and they get easy goals in front of our net and one in the corner. It’s not good enough.”

It wasn’t just that UMass squandered the game against its cross-state rival, it was how the Minutemen (18-10-2, 11-7-2 Hockey East) let the game slip away.

They entered the third period with a 2-1 lead and survived the early rush from a hungry UMass-Lowell (16-9-5, 10-6-4) squad. But after Matt Murray turned aside the first two shots he saw, UMass couldn’t clear the puck on the penalty kill and Carl Berglund poked home the tying goal.

Yet the game was still destined for overtime in the final seconds of regulation as UMass was setting up to clear its own zone. That was until the Minutemen didn’t and lost sight of the puck and stood around mystified. Meanwhile, Chris Schutz found the puck in the corner and sent it past an inattentive Murray into the net with 27.5 seconds left.

The pain from the loss was still sitting with UMass coach Greg Carvel when he walked into his postgame press conference. The fourth-year coach declined to give an opening statement and kept most of his answers brief with the anger and frustration emanating with every word he spoke.

“Two guys just stopped playing hockey,” Carvel said. “The goaltender just stopped playing hockey, it’s not a good time to do that.”

Adding to the frustration was a belief that UMass should have been leading by far more than a goal entering the third period. The Minutemen were the hungrier, more physical team in the opening 40 minutes and kept the River Hawks hemmed into their zone for extended stretches.

UMass didn’t make it difficult for Tyler Wall early, and still couldn’t find a way to create anything around the crease at even strength. The Minutemen might have outshot the River Hawks 16-2 in the first period and 14-9 in the second, but they couldn’t find a solution for Wall, who finished with 38 stops in the win.

“We needed to find a way to score a third goal,” Carvel said. “We were playing really well, had a lot of O zone time and what were the shots after two periods, 30-11? The only thing we’re not doing is scoring. You’re outshooting a team 30-11 and we’re only up by a goal, we’re usually a good third-period team and we let in two goals.”

The only saving grace for the Minutemen was the power play, which had been struggling just three weeks ago. But UMass was humming on the man advantage with its cycle and zone possession, tossing eight shots on net on their three power plays.

John Leonard tied the game on UMass’ first advantage of the evening, banging home a deflected Marc Del Gaizo point shot for his 50th career goal. The Minutemen then took the lead just two seconds after their third power play of the evening expired as Trivigno rocketed home a cross-ice feed from Jack Suter to give UMass the lead.

“We had a power play goal and we did exactly what we wanted to do – shoot the puck, get a tip and find a rebound after that,” Trivigno said. “Not bad but I feel like we could have scored on a few more chances.”

Coming back from an off week, the only sign of rust for UMass came from goalie Filip Lindberg. The sophomore let in an ugly goal on the first shot he saw, letting a routine shot squib past him, then let up a goal on the second shot he faced. The referees eventually overturned the second goal due to goalie interference, but Carvel had already made the change to Murray, who made 20 saves in relief.

Aside from the change in net, UMass used its physicality to muscle UMass-Lowell off the puck and create scoring chances. The Minutemen were forechecking better, efficient with their puck movement in the zone and putting plenty of rubber on Wall. Yet the scoreboard didn’t indicate that dominance in the most important column, something Carvel said will need to be fixed when the two teams meet Saturday night in Amherst.

“Score around the net like Lowell scored three goals around the net,” Carvel said about the key to Saturday’s rematch. “We’ve got to learn to score around the net.”

“We’ve got to get the pucks to the dirty areas and find a way to score,” Carvel added.