The Islanders goaltender stopped a career-high 42 shots, helping New York to a 4-2 win over the Buffalo Sabres on Friday night.
The victory, New York's second in less than a week over Buffalo, moved the eighth-place Islanders eight points ahead of the Sabres in the race for the Eastern Conference's final playoff berth.
``It's huge,'' DiPietro said. ``We realize there's still a lot of games left to play. But we realize how important this was. We didn't want to give them any momentum.''
DiPietro was key in stunting any momentum the Sabres attempted to generate early, stopping six shots in the first two minutes, and all 17 in the first period.
``We suspected they were going to come hard,'' Islanders coach Steve Sterling said. ``And Ricky was equal to the task.''
Oleg Kvasha had a goal and two assists, while Mariusz Czerkawski and Mattias Weinhandl had a goal and an assist each in helping the Islanders complete a four-game series sweep of Buffalo and beat the Sabres for the seventh straight time, going back to Oct. 10, 2002.
Roman Hamrlik also scored for New York, which inched to within a point of idle Montreal.
Chris Drury and J.P. Dumont each had a goal and an assist for Buffalo, which has lost three straight since ending a six-game unbeaten streak (5-0-1). It's been a dramatic turnaround for the Sabres who only a week earlier had crept to within three points of the Islanders and Montreal.
``It's not out of reach,'' coach Lindy Ruff said of the Sabres playoff status. ``But it's going to be tough. We need to fire on all cylinders.''
Buffalo appeared to be doing just that against New York, only to run into a hot goalie.
Besides his strong first-period effort, DiPietro secured the victory by stopping all 19 shots directed at him in the third. That included a three-shot flurry with 2:45 left.
DiPietro was sitting in the crease when Drury's backhander deflected off his mask. DiPietro then stopped Adam Mair from in close and Drury again, this time attempting a wraparound.
``He was unbelievable tonight,'' Kvasha said of DiPietro. ``It gives you confidence when the goalie plays like `Deep' played tonight. It gives you extra jump.''
After Dumont cut the Islanders lead to 3-2 with a power-play goal with 2:14 left in the second period, Kvasha sealed the victory, scoring 6:35 into the third.
It seemed fitting that Kvasha's goal came after DiPietro kicked out his left skate to get a piece of Dmitri Kalinin's point shot, which dribbled through a crowd.
The Islanders regained control of the puck with defenseman Kenny Jonsson leading an odd-man rush the other way. Jonsson crossed the Sabres' blue line and fed a pass across to Kvasha, who got a weak shot off that fluttered past handcuffed goaltender Martin Biron.
The game had a feel of a playoff meeting, opening at a frantic pace in which the teams combined for eight shots and several scoring chances in the first 2:15.
The Islanders, coming off Thursday's 6-3 loss to the New York Rangers, kept pace while playing their third game in four nights.
Bouncing back was an important motivator for the Islanders.
``Last night, I don't know what happened,'' Kvasha said. ``It's always good when you lose one to win the next one. The team feels better, guys start laughing and you get back to normal.''
Now it's the Sabres turn to regroup as they travel to play at Ottawa on Saturday.
``It wasn't a knockout punch,'' Mair said of the loss. ``We have a lot of hockey left.''