ORONO – Two momentum-shifters in hockey are shorthanded goals and goals scored in the final minute of a period.

University of Maine senior left winger and captain Todd Jackson accomplished both with one 25-foot snap shot.

Jackson’s fourth shorthanded goal of the season, coming with 39 seconds left in the first period, supplied the Bears with a 3-1 cushion en route to a 6-2 Hockey East victory over Merrimack College at Alfond Arena Thursday night.

Jackson, who added a power-play goal late in the third period, now has three game-winners and all three came while the Bears were shorthanded.

Maine, the nation’s No. 1-ranked team, improved to 6-0, which is the best start by a Black Bear team in the program’s 27-year history. It was Maine’s Hockey East opener.

Merrimack is now 2-3-1 overall, 1-2-1 in Hockey East.

“That was the biggest goal of the game,” said Merrimack senior center and captain Marco Rosa. “That was huge.”

The Bears’ Derek Damon chipped the puck ahead in the defensive zone to Jackson, and he banked it off the boards around Merrimack defenseman Tony Johnson, who elected not to risk taking a penalty by hauling Jackson down.

Jackson blasted around Johnson and broke down the left wing with Warrior defenseman Bryan Schmidt trying to get over to cut him off.

“I caught the defenseman [Johnson] flat-footed,” said Jackson. “I saw Schmidt coming off, so I just tried to get a quick shot off. It went short side.”

Merrimack goalie Casey Guenther said, “He caught me by surprise. He got the shot off quickly. It was a nice shot.”

“Todd has unbelievable speed and he’s able to transition from defense to offense on the penalty kill,” said sophomore right wing Greg Moore, who also had a pair of goals.

John Ronan opened the scoring by whacking home a second rebound after Guenther had stopped Mike Lundin’s point shot and Mike Hamilton’s follow-up.

Rosa equalized when Matt Johnson’s centering pass squirted free from Maine goalie Jimmy Howard at the near post and Rosa jammed it home.

Moore answered 4:35 later off a pass out from behind the net by Jackson.

“It deflected off their defenseman’s stick and I gloved it down and took a couple of whacks at it on the backhand,” said Moore.

“It went between my glove and my pad,” said Guenther, whose 15 first-period saves kept the Warriors close.

Maine, which outshot Merrimack 18-7 in the first period, did a great job limiting Merrimack’s scoring chances in the second period. The Warriors had only one high-percentage shot on goal.

Colin Shields expanded the lead to 4-1 when Michel Leveille won a faceoff and kicked it back to him at the top of the left circle.

“Our guys blocked out their forwards, so I took a low, hard shot,” said Shields, who beat Guenther to the short side.

Maine killed off a 52-second two-man disadvantage early in the third period, but Rosa made things interesting with a nifty redirection of a Matt Johnson pass into the upper corner to Howard’s stick side with 9:09 left.

Merrimack sustained some pressure, but Howard made a couple of good saves and Maine cleared the rebounds.

The Bears iced it on a five-on-three with 1:42 left when Moore tipped Lundin’s wrist shot between Guenther’s pads. Jackson closed out the scoring with a wrist shot from the left circle on a five-on-four power play 35 seconds later.

Maine outshot Merrimack 40-19 in beating the Warriors for the ninth straight time at Alfond Arena.

“I was very disappointed with the way we played,” said Merrimack coach Chris Serino. “We needed to do two things tonight: play smart and compete. We didn’t play smart and we competed for only 60 percent of the game.”

Maine will host Boston University on Saturday while Merrimack entertains RPI on Saturday night.

Moore and Leveille extended their points streaks to six games.

BLACK BEARS 6, WARRIORS 2

Merrimack (2-3-1) 1 0 1 ? 2

Maine (6-0-0) 3 1 2 ? 6

First period ? 1. Maine, Ronan 2 (Hamilton, Lundin) 4:30; 2. Mmk, Rosa 3 (Johnson, Schmidt) 9:13; 3. Maine, Moore 4 (Jackson, Damon) 13:48; 4. Maine, Jackson 6 (Damon, Ryan) 19:21 (sh). Penalties: Mmk, Wilson, hitting from behind, 0:16; Maine, Moore, roughing, 5:52; Mmk, Wilson, roughing, 5:52; Maine, Lundin, obstruction-interference, 18:12

Second period ? 5. Maine, Shields 5 (Leveille), 15:11. Penalties: Maine, Deschamps, tripping, 8:17; Mmk, Wilson, boarding and double minor for roughing, 12:26; Mmk, Pomponio, double minor for roughing, 12:26; Maine, Ryan, double minor for roughing, 12:26; Maine, Moore, double minor for roughing, 12:26; Maine, Damon, high-sticking, 16:35; Mmk, LaLonde, obstruction-tripping, 18:20

Third period ? 6. Mmk, Rosa 4 (Johnson) 10:51; 7. Maine, Moore 5 (Lundin, Shields) 18:16 (pp); 8. Maine, Jackson 7 (Barnes, Moore), 18:53 (pp). Penalties: Maine, Ronan, holding, 2:45; Maine, Johnson, hooking, 3:56; Maine, Leveille, roughing, 7:16; Mmk, LaLonde, roughing, 7:16; Maine, Leveille, roughing, 7:16; Maine, Penner, slashing, 9:46; Mmk, Hams, hooking, 9:46; Mmk, LaLonde, tripping, 16:22; Mmk, Pedersen, interference, 17:29; Maine, Mushaluk, cross-checking, 20:00

Shots on goal: Merrimack 7-3-9?19; Maine 18-7-15?40

Goaltenders: Merrimack, Guenther (40 shots-34 saves); Maine, Howard (19-17)

Power-play Opportunities: Merrimack 0 of 6; Maine 2 of 5

High-percentage scoring chances: Merrimack 4-2-3?9; Maine 10-3-7?20

Attendance: 5,501