It was not until Chris Connolly scored his third goal of the season with 28 seconds left that BU collected the victory, stretching its season-opening unbeaten streak to seven games.

BU is 6-0-1, 5-0-1 in Hockey East, and ranked sixth, but it might be difficult to say just why. BU didn’t put any kind of stamp on its victory until the final minutes, when the Terriers launched their first sustained flurry of shots at UMass-Lowell’s Doug Carr.

With a few minutes remaining and the game tied, 1-1, Joe Pereira pushed through a knot of players in front of Carr and hammered away at the puck until it disappeared. After officials reviewed the play, no goal was awarded.

But BU kept pushing, kept rushing the UMass-Lowell net. With the final minute counting down, BU junior defenseman David Warsofsky carried the puck down the left side of the zone, curled toward the net, and shoveled a pass out front to Connolly, who banged in the winner.

“I told [UMass-Lowell coach] Blaise [MacDonald], ‘If there was any justice, this would have been a tie, or even a loss for us,’ ’’ said Parker. “They really played us toe to toe all night. We didn’t play anywhere near as thorough as we have to, and they took advantage of that.

“When you don’t play your best and you win, you might say that’s pretty good. I’d feel better if this was road game — we just seem to be more la dee dah at home. The best we played tonight was the last 10 minutes of the third period, no question about that.’’

The River Hawks (1-4-2, 1-4-0), who struggled in a 5-1 loss to BU Friday night at Tsongas Center in Lowell, called the shots for most of last night’s game, attacking BU goalie Grant Rollheiser with five shots in the first five minutes, while the Terriers managed just two. BU was forced to absorb a five-minute penalty when Max Nicastro’s elbow sent UMass-Lowell’s Ryan Blair headfirst into the boards at 6:19 of the first.

Nicastro, a sophomore defenseman, was tagged with a major penalty and sent to the locker room with a game misconduct.

Still, the River Hawks couldn’t organize their power play, even with the extra time, or perhaps because of it. When the penalty was three minutes old, freshman Garrett Noonan cleared the puck from the BU zone, sending it the length of the ice, and the River Hawks were too eager to change lines and get back on the attack. A too many men on the ice call nullified the power play.

UMass-Lowell kept up its spirited attack in the second period, thwarted only by a strong game from Rollheiser (24 saves). UMass-Lowell’s aggressive play was not rewarded until 9:33 of the third period, when Joseph Pendenza knocked in a one-timer off a feed from Joe Caveney from behind the BU net to give the River Hawks a 1-0 lead.

“I was certainly happy with the way we played,’’ said MacDonald, who lost senior forward Patrick Cey in the first period to a lower-body injury. “Our guys played courageously, played with pace, played with pretty good structure. But BU is very tenacious.’’

After David Chiasson tied the game at 16:17 of the third, with BU outnumbering UMass-Lowell, 6-5, on a delayed penalty, BU picked up its pace. “When you’re playing the same team back to back,’’ Parker said, “whoever wins [the first game] feels a little too comfortable, and whoever loses feels like, ‘We’ve got to get back at it.’

“It was almost like, ‘OK, now we’ll play,’ or it might have been, ‘We’ve got to play now.’ After they scored, we picked it up from there, for sure.’’