The Rangers entered a home-and-home series against their archrivals needing just one win to seal their third straight trip to the postseason. They took care of business Thursday night with a 3-0 victory.
Jagr scored two power-play goals in the first period and Henrik Lundqvist made 25 saves for his 10th shutout of the season in his 70th game.
"Some days we were pretty lucky," Jagr said. "We scored last minute, last five minutes against New Jersey. We got those points. If we wouldn't have, we would be fighting for the playoffs. It is scary."
Philadelphia is currently in ninth place, on the outside of the playoff chase. The Flyers have 92 points, just three fewer than the Rangers.
"It's never been like that before," Jagr said. "You don't realize when the coach is telling you early in the season every game is so important. Now you can see that. You can make it by one point or two points. That's huge."
The Rangers are fifth in the East and still have their sights on the fourth-place New Jersey Devils and home-ice advantage in the first round of the playoffs. New York is two points behind with two games to play, and the area rivals will close the regular season against each other Sunday in New Jersey.
"It feels great to be in the playoffs -- again," Lundqvist said. "You never know what can happen with three games to go and you need one more point. It's good to get it over with right away. We played great."
The Rangers knew the injury-riddled, young Islanders would enjoy nothing more than to derail their postseason hopes. Jagr made sure early that wouldn't happen.
"We've got good people here," Islanders captain Bill Guerin said. "It's not an easy time for us to play, but guys are showing up and playing hard. Different people have different motivations, but we're working hard out there."
Jagr connected for goals 1:59 apart against goalie Wade Dubielewicz, and Martin Straka pushed the Rangers' lead to 3-0 at 7:39 of the third. Lundqvist made the offense stand up, earning his 17th NHL shutout.
In 90 career games against the Islanders, Jagr has 58 goals and 81 assists. No one has scored more goals versus the Islanders, and Jagr hasn't taken advantage of any team nearly as much.
New York missed the playoffs for seven straight seasons before this current streak, which began during Jagr's first full season with the Rangers.
"It's not about one guy. It's about the team," he said. "It's not easy to make the playoffs anymore. You have 30 teams, and half of the teams don't make the playoffs."
Jagr's scoring burst, coming in his worst offensive season since the 1991-92 campaign, had a large chunk of visiting Rangers fans at Nassau Coliseum derisively chanting "Season's over!" to the Islanders, who have long been eliminated from the postseason chase.
It marked the second straight home game for the Islanders that an opponent secured a playoff spot. The Devils got in with an overtime victory Tuesday.
"We know they want to wreck our party," said Brandon Dubinsky, who had two assists. "At the same time, we want to come in here and prove to them who the best team in New York is. We're happy to have won the game and I guess show them that we belong there."
Jagr needed a total of only 28 seconds of power-play time to post his second two-goal game of the season.
While Guerin was getting settled in the penalty box after being sent off for slashing, Jagr took a pass from defenseman Christian Backman and ripped a shot from the top of the right circle that slammed the right post and caromed in at 13:51.
Straka set a perfect screen in front, preventing Dubielewicz from picking up the puck before it clanged behind him.
Jagr made it 2-0 with 4:10 left in the period, and just eight seconds after Freddy Meyer was whistled for holding. Jagr received the puck inside the right circle and put a shot between Dubielewicz's pads for his 23rd of the season.
That gave the Rangers power-play goals in 7-of-14 chances over four games.
Straka fired a shot that hit Meyer in front and deflected past Dubielewicz to make it 3-0.
Newly signed defenseman Jack Hillen made his NHL debut with the Islanders. ... Rangers forward Brendan Shanahan sat out with a leg strain, but coach Tom Renney said he expects him to play Friday against the Islanders. ... Dubielewicz made 32 saves.