In addition to Garand and Sykora, Drew Fortescuehad an assist in his NHL debut. The three, who were not on the team a week ago, were named the three stars of the game.
Garand made several big saves, including a glove stop on Connor Bedard in front halfway through the first period, and Landon Slaggert's backhander on a mini breakaway with his left pad five minutes later.
He also stopped Slaggert on a breakaway with his blocker with 9:05 remaining in the third.
"He made a couple of big saves early in the game in particular,” Sullivan said. “I thought he looked really solid in there. And that's his second game in a row that I felt that way. It's two really good starts for him, and I'm happy for him because I know how hard he's worked to get to this point."
Nick Lardis scored for the Blackhawks (27-33-13), who lost for the sixth time in eight games (2-4-2) and remained 10 points behind the Nashville Predators for the second wild card into the Stanley Cup Playoffs from the Western Conference. Arvid Soderblom made 33 saves.
Chicago outshot New York 15-11 in the first period, but was outshot 16-4 in the second and allowed three goals.
"We had a pretty good first, we were in the game," Blackhawks forward Tyler Bertuzzi said. "Not much was going on, we were just playing simple and then I don't know what happened in the second and third. Something changed and we just weren't playing our game."
Lardis gave the Blackhawks a 1-0 lead at 17:34 of the first. Alex Vlasic toe-dragged around Rangers forward Will Cuylle before the puck came to Bertuzzi in front, who fed Lardis across the crease for a tap-in.
Miller tied the game 1-1 at 18:32 when Conor Sheary threw the puck in front and it deflected off his skate and went past Soderblom.
Matthew Robertson gave the Rangers a 2-1 lead at 5:24 of the second period. He collected the puck in the left circle after Miller’s shot was stopped and put a shot over Soderblom's left shoulder.
Sykora's first NHL goal put New York ahead 3-1 at 8:20. He scored with a wrist shot on a 2-on-1 with Cuylle.
"I saw a spot under the blocker, so I just saw it and tried to shoot it and then I (got) so excited after so I couldn't describe the feeling after," Sykora said. "... I enjoyed the moment and hopefully I'll get more."
Brodzinski increased the lead to 4-1 at 16:07 with a one-timer from the left circle.
Alexis Lafreniere added a power-play goal at 13:17 of the third period with a redirect of Adam Fox’s shot from the point to make it 5-1.
"It felt like we kind of just started to change up our style of play," Vlasic said. "I thought we had success in the first... For whatever reason, we kind of just got away from that and they were able to capitalize on our mistakes.”