The Boston University men’s hockey team knocked off the University of Massachusetts Lowell in a series-clinching 4-1 win Sunday at Lowell’s Tsongas Center.

“I thought we played a good hockey game from start to finish,” BU head coach Albie O’Connell said.

Having split the weekend’s first two games, the teams met for a third time Sunday to determine who would be advancing to TD Garden for next week’s Hockey East semifinals.

“We’ve been in this situation before,” O’Connell said, referring to BU’s experience in win-or-go-home contests.

Saturday’s Game 2 finished on a physical note, as brawls broke out after nearly every whistle late in the contest. Going into Game 3, it was clear that some bad blood had developed between the two teams, making the series-decider all the more contentious.

“We knew it was going to be a really physical and tough game,” freshman forward Joel Farabee said.

Among the aggression in Game 2, senior forward Bobo Carpenter took a hard hit in the final seconds, resulting in a suspension for UML forward Lucas Condotta. Carpenter’s status was uncertain Sunday morning, but at game time, the captain was there to take the opening draw.

Lowell (19-13-5) opened the scoring 3:37 into Saturday’s Game 2, but BU (16-17-4) one-upped the hosts in Game 3, striking first at the 2:34 mark.

Flooding the River Hawks’ end, junior forward Patrick Harper fed classmate Chad Krys joining the rush from his defensive position. The assistant captain made no mistake, scoring his first goal of the series to get BU off on the front foot.

“We came out fast, and they didn’t,” Farabee said.

The Terriers nearly made the lead two just past the period’s halfway point on a redirection by sophomore forward Logan Cockerill in front that got by netminder Christoffer Hernberg. However, the goal was disallowed, as Cockerill had tipped the puck with a high stick.

It did not take the Terriers long after the Cockerill chance to find their second tally, with Farabee coming through for his fourth goal of the series.

Krys was the provider on this occasion, moving the puck to Farabee as the clock ticked toward eight minutes left in the frame. Gaining the line, Farabee found space near the right dot and fired one by Hernberg to double the Terriers’ lead.

“I saw a little opening,” Farabee said. “It felt pretty good.”

BU threatened on a power play with 3:39 left in the period, as sophomore forward Ty Amonte got a pair of point-blank looks. While the Terriers’ man advantage was unsuccessful, BU didn’t wait long after for their third goal.

Junior forward Patrick Curry had set up the two Amonte attempts, and the third try proved to be the charm. Thirteen seconds after the power play expired, Curry found Harper, who whipped the puck home from close range to pot his first goal in six games.

In the Lowell net, Hernberg was replaced by New York Rangers prospect Tyler Wall, who had been the victorious netminder in Game 2.

“He wasn’t himself,” Lowell head coach Norm Bazin said about Hernberg. “You have those days as a goalie.”

The first period defensive effort from BU was as strong as the attacking output. The River Hawks were held to just three shots on goal in the opening frame, with none in the final 12 minutes.

“We didn’t generate enough shots tonight,” Bazin said.

With all the wind in their sails, BU took a 3-0 lead into the first intermission. It was sweet revenge for the visitors, who had been stunned Saturday night by the three first-period goals from the River Hawks.

“It was one of the best first periods we’ve had all year,” O’Connell said.

Having built up a three-goal advantage, the Terriers were content to sacrifice attacking threats in order to protect the defensive end. BU attempted eight shots on target in the second stanza compared to 13 in the first, and held Lowell to eight in the process.

Junior goaltender Jake Oettinger was rock-solid in the BU net, turning away River Hawks efforts from all angles. The assistant captain’s biggest stops of the frame came on a double-save to first deny forward Connor Sodergren’s attempts to jam the puck in the net and then keep out linemate Nick Master’s follow-up shot.

“I thought [Oettinger] made a couple really good saves,” Bazin said.

In addition to Oettinger’s stops, BU’s skaters tallied eight blocks in the period to match the keeper’s save total from the middle frame.

With 40 minutes in the books, BU’s 3-0 lead still stood, and so did their lopsided shots on target advantage, which had become 21-11.

As the hosts grew desperate as time in the third period ticked away, the River Hawks found hope with their first goal of the game with 12 minutes left in regulation.

With forward Connor Wilson holding the puck high in the attacking zone, the UML captain zipped a pass to forward Kenny Hausinger between the dots. The junior carried the puck to shooting position and found the top right corner to bring the score to 3-1.

Unfazed by the Hausinger score, Oettinger regained his rhythm, keeping Lowell to the lone goal as the River Hawks turned up the heat, seeking a late comeback.

“We couldn’t convert,” Bazin said.

Wall vacated the UML crease, and the Terriers’ defenders were rewarded in the final minute.

Withstanding River Hawks pressure, BU gained possession and quickly turned defense into offense. Cockerill led the break toward the gaping net and laid the puck off to a trailing Harper to tap home, completing the three-point night and securing the BU victory.

“[Harper] was terrific,” O’Connell said.

The teams skated out the final 52 seconds, and BU emerged victorious 4-1 in the game and 2-1 in the series.

“It’s no mistake that we came out and took care of business today,” Farabee said after the game.

The series win marks the eighth consecutive season in which the Terriers were able to advance beyond the first round of the playoffs.

“I’m really happy for our players,” O’Connell said. “Really excited for them.”

BU will move on to TD Garden for Friday’s Hockey East semifinals, taking on Northeastern University at 4 p.m. with a spot in Saturday’s tournament championship up for grabs.