TORONTO (AP) -- Three goals were good, 54 saves made the difference for the Philadelphia Flyers.
"He pretty much won that game for us," forward Mike Richards said.
Steve Downie scored his first NHL goal, Jeff Carter had his 14th of the season and Richards added his 19th to support Niittymaki. The Flyers bounced back from a shutout loss at New Jersey on Friday night to win for the fourth time in five games.
"Niitty stood on his head," Carter said. "He played a hell of a game."
"We played a good game, but it's like we don't know how to win the close games," Sundin said. "We have to become smarter and learn what it takes to win."
Each team lost a player to injury in the first period. Toronto defenseman Carlo Colaiacovo reinjured his right knee, and Philadelphia forward Joffrey Lupul was too woozy to continue after colliding with big teammate Derian Hatcher.
"Hopefully I'll feel fine in the morning," Lupul said. "I've got a big bruise and a little cut on my head but, other than that, I don't feel all that bad.
"I'll be re-evaluated [Sunay], but I feel a lot better now than when I was leaving the ice."
Toronto fell to 1-4-1 since goalie Vesa Toskala went down with a groin injury.
Downie, who was suspended for 20 games after a preseason hit on Dean McAmmond in Ottawa, skated in his second NHL game since being recalled from the AHL on Wednesday and his fourth overall.
The 20-year-old native of nearby Newmarket outmaneuvered Colaiacovo for position and slammed a rebound past Raycroft at 10:04.
Carter converted a 2-on-1 break into a short-handed goal at 16:28.
Sundin slapped in a drive from the top of the circle to Niittymaki's right at 4:09 of the third period during a power play. The puck caught the far side of the net on the glove side. Sundin then scored his 20th off at 11:48 of the third.
Richards got the winner at 17:09 while Ian White sat in the penalty box for holding.
"It was a gutsy win," Carter said. "We lost a couple of guys early and were down, basically, to 2 1/2 lines. We pulled out the win. These points against conference teams are going to be huge because (the standings) are so tight."
The 542nd and 543rd goals of Sundin's career moved him past Stan Mikita into sole possession of 25th place on the NHL's regular-season list. One more and he'll tie Maurice Richard.
"In the first half of the season we made a lot of mistakes," Sundin said. "We're good enough to be a playoff team ... but we're shooting ourselves in the foot on a lot of nights."
A weak power play again hurt the Leafs. They had six advantages, compared to two for the Flyers, but they managed only Sundin's goal.
Colaiacovo played in his fifth game after taking months to recover from head and knee injuries. ... Raycroft hasn't won since Nov. 9. ... Leafs C Nik Antropov hasn't scored in 11 games. ... F Kyle Wellwood returned to Toronto's lineup after being a healthy scratch for two games. RW Wade Belak also was a healthy scratch as was D Andy Wozniewski, whose place was taken by D Anton Stralman. ... Philadelphia was without D Jason Smith (bruised calf), LW Scottie Upshall (ankle) and C Simon Gagne (concussion). Gagne hasn't played since Nov. 7. ... Toronto is 13-11-4 with Toskala in goal, and 3-7-4 without him.