Playing without his injured linemate, Gagne got his NHL-leading 22nd and 23rd -- including the winner with 7:13 left -- and the Philadelphia Flyers rallied to beat the New York Islanders 4-3 on Tuesday night.
Forsberg, who assisted on 18 of Gagne's first 21 goals, missed his second straight game with a groin injury.
"Peter is very helpful when he is on the ice with me," said Gagne, who has seven multiple-goal games this season in only 23 contests. "Right now he's not here so maybe I have to give it a little bit more if I'm going to have a chance to score."
Gagne is back on pace to have 50 goals in 50 games.
"If everything is in place and the puck keeps going in like that, you never know," he said. "It's too early. If I get close to 40 I might think about it."
New York nearly tied it with 0.2 seconds left, but a video review revealed the puck didn't go in. There was no clear replay that showed if the puck crossed the line or if a stick was in the net.
"The puck went in, and the referee admitted that he had blown the whistle before the puck went in and apologized," Islanders captain Alexei Yashin said. "It was a really tough break. It would have been great to have the tie at that point and take our chances in overtime."
The Flyers, who trailed 2-0 after the first period, played without Forsberg and Keith Primeau but split the home-and-home series. Philadelphia has defeated the Islanders three times in four games.
The Islanders are 4-1 in their last five road games, including a win Saturday at Philadelphia, but they've dropped three straight at home.
"We seem to be more relaxed on the road, which leads to less penalties and lower expectations," Islanders coach Steve Stirling said.
Robert Esche stopped 20 shots and allowed fewer than four goals for the first time in five games. He dropped three straight decisions and didn't play in four of Philadelphia's previous six
contests. He refused to speak to reporters after the game.
Patrick Sharp scored the Flyers' other goal.
"We've blown so many games this year," defenseman Janne Niinimaa said. "Good teams don't let up when they have a lead. We did that tonight."
Sharp brought Philadelphia within 2-1 at 9:51 of the second with his fourth goal, all scored against the Islanders. He had a goal in Philadelphia's 5-1 win over New York on Oct. 15 and then got two in another Flyers' 3-2 home victory on Nov. 10.
After Parrish stretched New York's lead back to two goals with a power-play score just 1:40 later, Pitkanen converted a perfect pass from Gagne during a man advantage to make it 3-2 with 5:26 left in the period.
Gagne then tied it with Philadelphia's third goal of the period, with the teams skating four-on-four.
Kim Johnsson took a pass from Gagne and fired a shot that caught Snow high. Gagne charged in for the rebound and smacked the puck in to tie at 3 with 1:14 remaining.
"We deserved to be tied or ahead after the second period," Flyers coach Ken Hitchcock said.
New York made the most of its early chances, scoring twice on five shots in the first and then another on its ninth shot.
Satan gave the Islanders a 1-0 lead at 11:53 with his 13th goal. Standing alone in the left circle, he raised his stick and called for the puck. Niinimaa flipped it to him, and Satan deflected the puck out of the air and on a bounce past Esche.
Blake made it 2-0 with 2:05 left in the period on a power play. It was Blake's fourth goal in two games against the Flyers as he had a hat trick in New York's 4-2 road victory Saturday. He has six goals and 10 points in seven games.
Parrish scored the Islanders' second power-play goal when he deflected in Brent Sopel's shot while standing unchecked in front at 11:31. It was only the third goal scored by the right winger in 14 games.
Forsberg is expected to skate Wednesday and is questionable for that night's home game against New Jersey. ... The Islanders recalled center Wyatt Smith and Sean Bergenheim from AHL Bridgeport to fill in for injured forwards Oleg Kvasha (ankle) and Shawn Bates (hamstring). Kvasha was injured Saturday at Philadelphia.