Hoffman had a rebound and an open net to the right of Murray, but the Pittsburgh goalie dove across to knock a shot off the goal line with his glove.
The play was reviewed, but the call on the ice stood as replays showed the puck never crossed the line and barely rolled to the outside of the post. The patient Penguins regrouped and went on to a 3-1 victory over the Ottawa Senators.
''It looks like it's a for sure goal with the play they made and (Murray) looks like he was down and out and finds a way to get his glove on it,'' Pittsburgh captain Sidney Crosby said.
''That's a big point in the game and if they score that they get some momentum and it's a different outcome.''
Murray made 21 saves for the win and faced just 12 shots over the final two periods.
''It was nice to get a road win,'' Crosby said. ''They're not a team that gives you a lot so we had to play a patient game and we generated some good chances.''
After Murray's big save in the first, the Penguins took control and allowed only one good scoring chance the rest of the way on a breakaway goal by Jean-Gabriel Pageau at 10:29 of the third period.
Craig Anderson turned aside 26 shots for Ottawa (8-4-5), who won its previous two games.
''I thought we had a good start but it's hard to come back from two goals against a good team like that,'' Pageau said.
''I thought we played better than them in the first and obviously a good team is going to bounce back. They did play a better second than us.''
''We got away from what we did in the first,'' he said. ''In the first we were foot to the floor, we were getting pucks to the net, and in the second we couldn't get any flow. It was kind of a disjointed game.''
The teams played a tight-checking game through the first 10 minutes of the third period as both sides had just one shot on goal.
''We were patient, we took plays when they were there and when we didn't we got pucks deep and we went to work,'' Penguins coach Mike Sullivan said.
''I think that's the type of game you have to play against a counter-attack team like Ottawa. I thought our guys really bought in.''
NOTES: Hoffman also hit the crossbar behind Murray eight minutes into the game. ... Nick Paul was the lone scratch for the Senators. Scratches for the Penguins were Frank Corrado and Josh Archibald. ... Senators forward Zack Smith was placed on injured reserve with a thumb injury. ... The Penguins are 7-1-2 in their last 10 games against Ottawa.
Penguins: Host the Chicago Blackhawks on Saturday night.
Senators: Host the Arizona Coyotes on Saturday night.
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