The Sabres entered the night 4-for-18 on the power play (22.2 percent). In three wins, they've gone 4-for-9. They're now 0-for-15 in three losses.
The key to more consistency, rookie forward Casey Mittelstadt said, could be as simple as getting more shots to the net. The Sabres registered eight shots on their six attempts Tuesday.
"I think it gets hard doing the same things," Mittelstadt said. "I think we've just got to start shooting the puck. When you start struggling on the power play you usually try to get too cute. At times for us, that was what it was tonight."
The Golden Knights were returning home from a five-game road trip, which they capped with a shutout win in Philadelphia on Saturday. With a raucous home crowd at T-Mobile Arena, the Sabres were expecting a strong push to open the game.
They got it. The Golden Knights outshot the Sabres 12-5 in the first period and out-attempted them 21-10. But the Sabres were able to weather the storm until a holding call against Marco Scandella put the Golden Knights on the power play late.
Marchessault opened the scoring with 1:01 remaining, burying a crossing feed from Karlsson on the rush. An early power play gave the Sabres a chance to turn the momentum in the second period, but a turnover at the Vegas blue line led to Eakin's goal at the other end.
"I think we weren't real sharp with our execution," Housley said. "When we were good coming out of our end we had this push and we had some zone time. But you could see just the lack of execution.
"You can't turn pucks over on this team, they feast on it. They're very aggressive on the transition and they come back at you."
The Sabres felt they could still salvage the game down 2-0 heading into the third, but they were held off the board until Vladimir Sobotka buried a rebound to spoil Marc-Andre Fleury's shutout bid with 36.7 seconds remaining. Marchessault answered with an empty-net goal 24 seconds later.