Stepan tallied once in the first period and twice in the middle stanza to become the first rookie to score three times in his debut since Fabian Brunnstrom of the Dallas Stars on October 15, 2008. He also became the first player in Rangers history to turn the trick in his first-ever game and the first Blueshirt since Ron Murphy on October 7, 1955 to do so on Opening Night.
Brandon Dubinsky scored twice and Henrik Lundqvist turned away 33 shots to record the victory for the Rangers.
Jordan Leopold scored twice and added an assist while Ryan Miller stopped 22 shots in defeat for the Sabres, who edged Ottawa, 2-1, in their season opener Friday night.
Stepan deflected a Dan Girardi shot from the right point off Buffalo defenseman Tyler Myers past Miller to give the Rangers the lead just under 11 minutes into the game.
Myers lost his edge behind the net, which allowed Artem Anisimov to get to the puck and circle around right side of net from where he fed in front to Dubinksy, who tipped it home to make it 2-0 five minutes later.
Leopold got the Sabres on the board with a slap shot past Lundqvist 11 minutes into the middle period, but the Rangers countered with two tallies from Stepan.
The Hastings, Minnesota native took a rebound from a Marc Staal shot on the left doorstep and wristed it past Miller to make it 3-1 four mintues later.
Girardi pinched down the right boards from the blueline and shoveled the puck behind the net from where Sean Avery delivered a backhand pass to Stepan on left side of the crease and he snapped it home with 1:40 left in the second.
Marian Gaborik passed from behind the net to Erik Christensen in the slot and he snapped it by Miller to extend the lead to 5-1, 1:08 into the final stanza.
Leopold scored his second goal of the night on the power play on a one-timer from the mid-point that squeezed through the pads of Lundqvist to cut the lead to 5-2 with just over 14 minutes to play.
Tyler Ennis threw the puck in front from his knees behind the net and Derek Roy was there to pick up the deflected disc and wrist it over Lundqvist to make it a two-goal game with 5 1/2 minutes left.
Dubinsky’s short-handed empty net goal with 1:25 left sealed the victory.