Stefan Demopoulos scored the lone goal and Jon Gillies made 37 saves as PC (11-10-6, 9-6-5) captured the season series (2-0-1) between the teams for the first time since the 1995-96 campaign.
Mark Jankowski carried the puck deep into the right end and then slid it to Demopoulos who picked the upper-left corner with 2:48 left in regulation.
As a result, the fifth-ranked Wildcats (16-8-3, 11-7-2) were unable to overtake Boston College (17-7-2, 12-6-1) for first place in the league.
"A lot of credit goes to them," UNH's Connor Hardowa said. "They played a good game. It was a big transition game and both teams had a lot of chances.
"Both goalies played amazingly. Obviously, it was big for (Casey) DeSmith (33 saves) to make that penalty-shot save and Gillies made a lot of great saves as well. They just got the last laugh on this one."
The play Kardowa referred to came at the tail end of the second period.
Shortly after Ross Mauermann came out of the box after serving a minor penalty, he was pulled down from behind by Justin Agosta which resulted in a penalty shot for the Friars.
Mauermann skated down the middle and unleashed a forehand drive which DeSmith snared with 54.9 seconds left in the period.
"At the time, it was a big thing for DeSmith," Kardowa said. "Obviously, to make a big save like that on a penalty shot is something to brag about.
"It was big for him. It was big for our team to get a little jump there. It gave us a little bit of a boost but obviously it wasn't enough."
The first period ended in a scoreless tie due in large part to UNH center Kevin Goumas.
Mauermann unloaded a shot midway through the period and the puck trickled off the pads of DeSmith toward the goal line. But Goumas came out of nowhere to slap away the puck and prevent what would have been a sure goal.
"It was unfortunate that we gave up a goal with a couple of minutes to go," coach Dick Umile said. "We had our chances on the power play. Both goalies played well and they got the bounce at the end."
The fact UNH was 0-for-6 on the power play really irked Umile.
"That hurts because you have to score on the power play, especially at the end of the season when you start playing playoff hockey," Umile said. "And this is playoff hockey.
"We got some good looks but I think part of it was goaltending and Providence doing a good job on the penalty kill. They didn't score on us on the power play (PC was 0-for-4) so I think both teams did a pretty good job. The got the goal when they needed it. We didn't get a clear, it came back in our face and they scored."
Including Wednesday's game at Providence, the Wildcats will play their last four games of the month on the road ... UNH visits Conte Forum for a key Hockey East game on Sunday afternoon against Boston College before traveling the following weekend to Vermont for a pair of games.