Fox became the second defenseman in NHL history with multiple four-assist games in the Stanley Cup Playoffs. Hockey Hall of Fame member Paul Coffey did it four times.
"I'm just trying to move the puck to the right guys, and obviously it's nice to contribute like that," said Fox, who had four assists in a 5-3 win at the Pittsburgh Penguins in Game 6 of the first round last season.
Chris Kreider scored two power-play goals, Filip Chytil had a goal and an assist, and Artemi Panarin had two assists for the Rangers, the No. 3 seed in the Metropolitan Division. Igor Shesterkin made 27 saves.
Jack Hughes scored on a penalty shot, and Vitek Vanecek made 18 saves for the Devils, the No. 2 seed in the Metropolitan, who went 0-for-4 with no shots on goal on the power play.
"We've just got to put more pucks on the net (on the power play)," New Jersey captain Nico Hischier said. "They blocked a lot of shots (23), and I think Shesterkin made some huge saves. They could have gone in at some point, but we lost that game and now we look forward to the next game."
RELATED: [Complete Devils vs. Rangers series coverage]
Game 2 of the best-of-7 series will be here Thursday (7:30 p.m. ET; TBS, SN360, TVAS2, MSGSN, MSG).
"We talked about managing the puck, not getting turnovers and giving them odd-man rushes, and I thought we skated hard," New York coach Gerard Gallant said. "But the biggest thing for us is we forechecked well. We did a good job in their zone, and we didn't spend as much time in our zone."
Vladimir Tarasenko gave the Rangers a 1-0 lead at 4:58 of the first period when he swept a shot along the ice from the slot just inside the right post.