For the third time this season, Union had another bad first period.

Unlike the previous two times, the Dutchmen weren’t able to erase the deficit. Going 0-for-11 on the power play didn’t help, either.

The Dutchmen fell behind, 3-0, in the first period against Dartmouth, got to within one after two, but couldn’t get the tying goal and dropped a 5-2 decision in their ECAC Hockey opener Friday at Messa Rink.

The loss snapped Union’s five-game unbeaten streak (2-0-3) against Dartmouth at Messa.

“We were opportunistic,” Dartmouth coach Bob Gaudet said. “I thought Union played very well. We had some chances that we buried that put us up.”

Union (0-1 ECACH, 3-2-1 overall) overcame a 4-0 deficit to beat Quinnipiac, 6-5, in the season opener Oct. 17. A week later, the Dutchmen fell behind, 1-0, to Rensselaer Polytechnic Institute in the Governor’s Cup before winning, 2-1, in an overtime shootout.

There would be no such victorious comeback this time, even though the Dutchmen had a 49-37 shot advantage.

“We have to execute a little bit better,” Union coach Nate Leaman said. “They scored on the first shot, they scored on their fifth shot and they scored on their 11th shot. We had 22 shots, and didn’t score a goal. I thought we dug ourselves a hole.”

The first four Dartmouth goals were the result of horrendous defensive breakdowns.

Brendan Milnamow was flat-footed at the Union blue line, and couldn’t recover in time as Scott Fleming skated past him and blasted a shot past goalie Cory Milan 54 seconds into the game.

Andrew Owsiak scored on a 2-on-1 break with seven minutes left in the first. Lane Caffaro couldn’t handle a Kelly Zajac pass as he cut into the slot, creating the 2-on-1. Fleming scored a power-play goal on a breakaway with 1:11 in the first.

“We were just making uncharacteristic, bad, dumb plays,” Caffaro said. “Sometimes, you make a bad play and give up a chance. But we were giving high-quality chances.”

The Dutchmen cut the deficit to 3-2 on second-period goals by Adam Presizniuk and Caffaro. But midway through the third period, Caffaro failed to cover Joe Stejskal coming out of the penalty box. Stejskal, who was serving his fourth penalty of the game, took a Fleming pass and fired a slap shot past Milan.

“Lucky is the word for it,” Stejskal said

Ken Schott covers college hockey for the The Daily Gazette in Schenectady, N.Y.