BOSTON — For the first time since 2009, the Boston University Terriers are kings of Hockey East.

BU knocked off two-time defending champion UMass Lowell 5-3 on Saturday at TD Garden, continuing what has been one of the greatest turnarounds in college hockey this season.

The Terriers lost 21 games last season and were eliminated before the Garden rounds of the conference tournament for just the second time since 2001. Now, in the second season under head coach David Quinn, BU will enter the national tourney as a No. 1 seed with a clear path to the Frozen Four, which, coincidentally, will be held in Boston ice next month.

At the center of that turnaround has been Jack Eichel, the freshman sensation all but guaranteed to be the first or second pick in the 2015 NHL draft. Eichel has been the best player on the ice all season for the Terriers and was so again Saturday, netting two goals and adding an assist in the win.

The three points brought the 18-year-old’s season total to 66 — the most ever scored by a BU freshman and the most by any freshman since Paul Kariya racked up 100 in 1992-93. Eichel was named the Hockey East tournament’s MVP after tallying 11 points (six goals, five assists) in four games.

The tone of Saturday’s tilt was clear from puck drop. Felled bodies and loose sticks covered the ice as each team attempted to impose its will on the other.

BU’s Evan Rodrigues and Lowell’s C.J. Smith received matching roughing minors after an altercation behind the Terriers’ net at the 7:25 mark of the first — Smith leveled defenseman Matt Grzelcyk with a late hit, and Rodrigues and Danny O’Regan came to their captain’s aid — and a goaltender interference call on Dylan Zink four minutes later gave BU its first power play.

The Terriers quickly capitalized, with Grzelcyk scoring off a feed from Eichel just 21 seconds into the man-advantage.

“The goal, I think, was all Jack,” said Grzelcyk, a Boston Bruins draftee. “He’s the one who skated up the ice and kind of beat a few guys, and I think he saw me going to the net and trying to make a play. Luckily, I went right off the (defenseman’s) stick and right to me, and I just tapped it in.”

It was not the best period for Zink. Two minutes after Grzelcyk’s tally, Eichel dangled around the sophomore blueliner before sliding a shot underneath River Hawks forward Joe Gambardella and between the legs of goalie Kevin Boyle to make it 2-0 Terriers.

Eichel’s tally was the third shot to get by Boyle in the frame, but officials waved off the second — a Nikolas Olsson goal — after determining Olsson had been offsides when when he entered the UML zone. That, coupled with a power-play goal by Gambardella in the final minute of the frame, allowed the River Hawks to avoid utter disaster in the first.

The Terriers, however, just kept on coming. Senior alternate captain Cason Hohmann scored five minutes into the second to make it 3-1, and Olsson redeemed himself by beating Boyle with 45 seconds remaining in the period, finishing off a textbook 2-on-1 with Grzelcyk to do so.

UML struggled to solve BU netminder Matt O’Connor, who finished with 22 saves and robbed River Hawks captain Zack Kamrass with a terrific glove save during a second-period power play.

Lowell did get two goals in the final period, one each by Michael Louria and Michael Kapla, but a second Eichel tally with 5:17 to play proved to be all the insurance BU needed.

The Terriers now have hoisted all three major trophies they’ve competed for this season — the Beanpot, the Hockey East regular-season crown and the conference championship. Next up is the ultimate goal: An NCAA title.

Thumbnail photo via Twitter/@theScoreNHL