After being credited with the opening goal, which caromed off several skates, Stepan scored twice 3:12 apart late in the second period to complete the hat trick and put the Rangers ahead 4-1.
Brandon Dubinsky scored twice and Erik Christensen added a goal for the Rangers.
Buffalo defenseman Jordan Leopold scored twice and added an assist, and Derek Roy also scored for the Sabres in their home opener.
At Washington, Alex Ovechkin beat Martin Brodeur with a penalty shot to complete Washington’s four-goal second period in a win over New Jersey.
Ovechkin finished with two goals and an assist. John Carlson had a goal and two assists for Washington, which won its ninth straight home opener — a streak that began with a victory over New Jersey in 2001.The Capitals got 31 saves from Michal Neuvirth.
Jason Arnott and Henrik Tallinder had goals for the Devils, 0-1-1 under first-year coach John MacLean. Brodeur stopped only 15 of 20.
At Stockholm, Ethan Moreau scored 1:56 into overtime to give Columbus a victory over San Jose and a split of the two-game series in Sweden.
Kristian Huselius and Rick Nash also scored and Steve Mason made 33 saves for Columbus.
Joe Thornton and Devin Setoguchi had goals for San Jose.
The Sharks beat the Blue Jackets 3-2 on Friday night.
At Prague, Radim Vrbata scored twice and added an assist to lead Phoenix past Boston in their NHL season-opening game in the Czech capital.
Nathan Horton scored twice for Boston in the third period.
Vrbata, a Czech right winger, scoring on a rebound of Adrian Aucoin’s shot 7:59 into the game.
The Coyotes took a 4-0 lead in the second period on goals by Taylor Pyatt, Scottie Upshall and Eric Belanger.
Phoenix and Boston will play the second and final game of their series in Prague on Sunday.
At Pittsburgh, Mike Cammalleri and Scott Gomez scored in a 24-second span over the final 2:12 as Montreal rallied for a win over Pittsburgh.
Cammalleri’s second goal of the game was scored when he deflected Josh Gorges’ shot from the right-wing boards, getting it past Pittsburgh goalie Marc-Andre Fleury. Gomez scored on the next shift.
Evgeni Malkin and Mark Letestu had goals for the Penguins, who were beaten at home by Philadelphia on Thursday.
Cammalleri also scored in the first period for the Canadiens.
At Tampa, Florida, Steven Stamkos had two goals and an assist to help new Tampa Bay coach Guy Boucher win his NHL debut.
Stamkos had 51 goals last season to tie Pittsburgh’s Sidney Crosby for the league lead. Steve Downie, Dominic Moore and Vincent Lecavalier also scored for the Lightning in their season opener.
Atlanta, which trailed 4-0 in the second period, got goals from Tobias Enstrom, Ben Eager and Chris Thorburn.
At Uniondale, New York, Mike Ribeiro beat goalie Rick DiPietro with a strong backhand-to-forehand move in the final round of a shootout to lift Dallas over the New York Islanders.
Brenden Morrow scored twice, and Jamie Benn and Stephane Robidas added goals for the Stars, 2-0 this season after back-to-back road wins following regulation. Dallas won 4-3 in overtime at New Jersey on Friday night.
Brad Richards and Ribeiro added two assists, and Kari Lehtonen posted 43 saves for the victory.
James Wisniewski, Doug Weight, Blake Comeau and Moulson scored in regulation for the Islanders.
At Toronto, newcomers Kris Versteeg and Clarke MacArthur each had a goal and an assist as Toronto beat Ottawa.
Nikolai Kulemin, Phil Kessel and Tim Brent also scored and Jean-Sebastien Giguere made 17 saves for Toronto.
Jason Spezza scored for Ottawa.
At Nashville, Tennessee, Steve Sullivan scored a power-play goal and had an assist in the second period as Nashville opened the season by beating Anaheim.
Marcel Goc, Patric Hornqvist and David Legwand added goals for Nashville. Shea Weber, chosen as Nashville captain in July, also had two assists as the Predators won their opener for the fifth time in seven season.
Saku Koivu scored the first goal of the season for the Ducks, who have lost the first two game of a three-game, season-opening trip.
At St. Louis, Carlo Colaiacovo scored 1:47 into overtime to lift St. Louis over Philadelphia.
The Blues also got a goal from Brad Boyes. Alex Steen had two assists, and Jaroslav Halak stopped 29 shots in his St. Louis debut.
The Flyers got a goal from Danny Briere — his second in two games.
At Chicago, Valtteri Filppula’s second goal of the game snapped a third-period tie as Detroit spoiled Chicago’s Stanley Cup banner-raising celebration.
Todd Bertuzzi had a goal and assist for the Red Wings (2-0).
Brent Seabrook and Bryan Bickell scored for the defending champion Blackhawks (0-1-1) in their home opener.
At Vancouver, British Columbia, Anze Kopitar and Jack Johnson scored shootout goals for Los Angeles, which rallied late and beat Vancouver in the season opener for both teams.
Justin Williams leveled it on a power play with 4:05 left in regulation, and the Kings had a glorious chance to win it on another advantage late in overtime.
Defenseman Christian Ehrhoff scored a power-play goal in regulation for Vancouver.
