After 12 Rangers failed to come close to scoring, Hossa finally finished off one of the longest shootouts in NHL history. The Rangers, of course, know a little something about winning long shootouts. They went 15 rounds to beat Washington last season.
Simon Gagne scored twice and Peter Forsberg had a goal and an assist in regulation for the Flyers, who lost their home opener and remained winless (0-1-1) this season.
Niittymaki had 26 saves in his first game since deciding to have a cortisone shot instead of surgery to repair a torn labrum in his left hip. Joni Pitkanen added two assists for the Flyers.
While last year's Flyers started the season as a trendy Stanley Cup pick, this year's team hasn't even been considered a favorite in the Atlantic Division. A dismal 4-0 loss to Pittsburgh in the opener did little to boost confidence, and the Flyers heard plenty of boos at the end of this one.
Hossa was the 26th skater overall in the shootout, and the only one to score.
Philadelphia's best shot in the shootout came when Mike Richards knocked one off the crossbar on its second chance. Henrik Lundqvist, who had 35 saves, was hardly challenged the rest of the way.
The Flyers wasted a power-play opportunity in the waning minutes of the game, with Lundqvist making two clutch stops to send the game into overtime. The Flyers outshot the Rangers 35-29 in regulation.
Philadelphia never took a shot on another power-play chance with 13.1 seconds left in overtime. The Rangers had only one shot in overtime.
Adam Hall tied the score at 4 on a goal midway through the third.
The Rangers needed only 42 seconds to grab a 1-0 lead on Michael Nylander's first goal.
Wearing the "C" on his sweater for the first time at home as a Flyer, Forsberg tied it on a two-man advantage. Gagne put them ahead late in the period on a slap shot from the right circle.
Michal Rozsival was left all alone and unchallenged to flick one past Niittymaki early in the second that tied it 2-all. About 3 1/2 minutes later, Niittymaki caught another bad break when Thomas Pock's pass off the board took a surprising slice back in front of the net that Matt Cullen had no trouble dumping in the net for a 3-2 lead.
Niittymaki seemed to have no trouble with movement in any direction nearly two weeks after he tore the labrum in his left hip in practice. Now he's locked in a battle for the starting job with Robert Esche, who struggled against the Penguins.
The Flyers evened the score in the second on their second power-play goal of the game with Hossa out on a high sticking. Geoff Sanderson skated halfway behind the net before abruptly shifting direction, coming back around the net and sliding one past Lundqvist.
Gagne, who signed a five-year contract before training camp, delivered a go-ahead goal again when he picked up a loose back and snapped a wrist shot from the slot.
Notes: Flyers D Mike Rathje is out indefinitely because of a herniated disc in his back and will have more tests Monday to decide if he needs surgery or rehabilitation. Flyers trainer Jim McCrossin said surgery would keep Rathje out about four weeks. If not, he could miss up to two weeks. However, D Denis Gauthier did return after missing the opener with a head injury. . . . There was a pre-game video tribute celebrating 40 years of Flyers history and the 1967-68 team was honoured at the first intermission. The fans booed the Eric Lindros highlights.