The New York Rangers inflicted a rare home defeat on Chicago, beating the Blackhawks 3-2 to prevent them extending their Central Division lead.
New York's winning goal came with 5:57 left. Marc Staal started the winning sequence with a long slap shot that was stopped by Corey Crawford, who also blocked Carl Hagelin's rebound attempt.
But Hagelin flipped the puck into the open right side of the net.
Brad Richards and Mats Zuccarello also scored for New York, which earned its first win in Chicago for five years.
Jonathan Toews and Brandon Bollig scored in the second period for Chicago, which lost in regulation for the first time in 11 years.
Philadelphia's Sean Couturier, Zac Rinaldo and Michael Raffl scored to lead the Flyers past Montreal 3-1.
The surging Flyers have surged to fourth in the Eastern Conference, and are on their longest home winning streak for 10 years.
Tomas Plekanec scored for the Canadiens. Colorado's Paul Stastny had the tying goal and two assists and Tyson Barrie scored 33 seconds into overtime to complete the Avalanches' 4-3 comeback victory over Ottawa.
Jan Hejda and Jamie McGinn also scored for Colorado. Clarke MacArthur had a goal and an assist for Ottawa, and Jason Spezza and Kyle Turris also scored.