At the end of one period against Boston University last night, the Harvard men’s hockey team was outplaying the No. 5 team in the country. The Crimson entered the locker room with a 1-0 lead.

“The first 20 minutes, we played very well,” Harvard captain Peter Capouch said. “We proved we can definitely play with good teams.”

The second period, however, was a different story. The Terriers exploded for five goals and eventually cruised to an 8-4 win at the Bright Hockey Center.

It was the first victory for the Terriers (7-1-1) since losing to Boston College last Saturday night. For Harvard (3-3-1), the loss ended a three-game unbeaten streak.

As has been the case at various points this season, Harvard was hurt by penalties last night. The Crimson was called for nine penalties, and BU made Harvard pay, going three-of-five on the man advantage. Two of those goals came in the decisive second period.

For the second straight game, Harvard Coach Mark Mazzoleni stressed the need to eliminate penalties that are fast becoming the Crimson’s Achilles’ heel.

“They were opportunistic on the power play,” Mazzoleni said of BU. “They made the plays when they needed to make the plays.”

Harvard soundly outplayed BU in the opening period. Sophomore forward Tim Pettit continued to display a knack for the net, notching the game’s first goal at 15:05 of the first period.

It was Pettit’s fifth goal of the year, and all of them have come on the power play.

On the scoring play, sophomore forward Tyler Kolarik directed a pass towards captain Peter Capouch in the corner. Capouch made an excellent pass across the ice to find Pettit just inside the blue line. With freshman Tom Cavanagh screening BU goaltender Sean Fields, Pettit unleashed a blast that found the back of the net and put the Crimson up 1-0.

Harvard played strongly for the remainder of the first period, skating quickly and checking hard. After the first intermission, however, its play took an ugly turn.

Harvard started the second period on the power play, but was unable to capitalize on a roughing penalty charged to BU’s John Sabo.

BU then proceeded to dominate Harvard, outplaying the Crimson in every facet of the game. Five goals later, Harvard trailed 5-2 entering the third.

The BU goals were scored by freshmen Ryan Whitney and Brian McConnell, sophomores Frantisek Skladany and Gregg Johnson, and captain Mike Pandolfo.

“We have to tighten up things in our own zone,” Capouch said. “We run a pretty simple zone coverage, and it broke down tonight.”