DiPietro, who missed three games due to a head injury, turned aside 35 shots, and the Islanders snapped a four-game losing streak by beating the Pittsburgh Penguins 3-1 Thursday night.
"I believe we have confidence in our game with Ricky in there," Islanders coach Ted Nolan said. "He was one of the big reasons we won."
The man with the 15-year contract has 31 of New York's 35 wins with a 2.51 goals-against average and .919 save percentage. The Islanders returned home from an 0-3-1 trip, a stretch in which DiPietro missed mostly all but the final game.
Trent Hunter, Jason Blake and Viktor Kozlov scored for the Islanders after spotting the Penguins a 1-0 lead. The Islanders moved one point ahead of Toronto and into 10th place in the Eastern Conference playoff race. They trail Carolina and Montreal - at the playoff cutoff - by one point but have games in hand.
"Every point is a big point, and the whole team has to respond," Kozlov said. "If we can continue to play the same way every game, we'll have a good chance."
Colby Armstrong scored and Marc-Andre Fleury stopped 29 saves for the Penguins, who after a defeat at the New York Rangers on Monday, have lost consecutive games in regulation for the first time since Jan. 9-10.
"It was good, hard hockey," Penguins forward Mark Recchi said. "We just want to keep trying to do the things we do best to win games."
The Islanders also snapped Pittsburgh's 16-game point streak with a 6-5 victory on Feb. 19. The Penguins remained two points behind New Jersey in the Atlantic Division race.
Penguins 19-year-old phenom Sidney Crosby was held scoreless for the second straight game, following a six-game point streak.
"He made some good saves," Crosby said of DiPietro, "but we also didn't put in a bunch of pucks with an open net or behind him."
Both goalies made big saves in the first period to keep the game scoreless.
DiPietro got his stick down on the goal line to stop Michel Ouellet's rebound try at 9:56, and Fleury kicked out his left pad to stop Miroslav Satan during an Islanders power play at 13:45.
Armstrong finished a 2-on-1 with Gary Roberts by redirecting Roberts' cross-ice pass past DiPietro to give the Penguins a 1-0 lead at 16:55.
"One of the things we have to do to be successful is to keep the number of odd-man rushes down," Islanders defenseman Brendan Witt said. "We've been giving up six, seven a game. Tonight, we held them to one or two, but unfortunately, they scored on one."
New York tied it at 2:37 of the second on Hunter's power-play goal. Satan quickly fed the puck to Hunter in the slot for a wrist shot that beat Fleury and gave the Islanders forward 20 goals this season.
The Islanders took a 2-1 lead at 5:43 when Blake sent an uncontested wrist shot from inside the left circle past Fleury.
DiPietro held the lead when he made a right pad save on Evgeni Malkin's first NHL penalty shot at 6:26. The puck trickled toward the goal line, but DiPietro smothered it with his glove before it went in. Malkin was given the chance when he was hooked down by defenseman Tom Poti on a breakaway.
"The guy is a dynamic player," DiPietro said. "I was glad to get a leg on it and then cover it up."
Shortly after that, the Islanders had to kill two straight penalties, with 37 seconds of overlapping time for a two-man Pittsburgh advantage.
"That was a big key," Witt said. "We were able to hold them off."
Kozlov scored his 22nd goal at 1:42 of the third period, tying his career high.
Alexei Yashin, who assisted on the goal, had been demoted and benched after a lapse in defensive coverage during Tuesday's 4-3 overtime loss in Tampa. He was shuffled between lines, and saw power-play time against the Penguins.
"He (Nolan) told me what he wanted me to do," Yashin said. "I went out there and tried to do what he asked."
Both sides agreed the game was exceedingly rough.
"Games tend to get physical at this time of year when points are on the line," Nolan said. "It was a chippy affair."
Notes: Suspended New York forward Chris Simon talked to his teammates before the game. ... Islanders forward Jason Blake played in his 499th NHL game. ... Pittsburgh is 8-3-1 in March. The Penguins' first two losses in the month were by one goal.