Mercer, who had an assist, has 20 points (11 goals, nine assists) during the streak.
"He's playing a great 200-foot game right now," Devils forward Tomas Tatar said. "He's very good at every zone in the ice, and it's fun to watch him."
Nico Hischier had a goal and an assist, and Akira Schmid made 23 saves for New Jersey (43-16-6), which is 6-1-1 in its past eight games.
"They're a better group than their standings show, I think, so it's a good game for us," Devils defenseman Ryan Graves said. "You need to win these games this time of year. The points are huge for us right now."
The Devils are in second place in the Metropolitan Division, two points behind the Carolina Hurricanes, who lost 4-0 to the Vegas Golden Knights on Saturday and have one game in hand.
New Jersey hosts Carolina on Sunday (7 p.m. ET; SN360, SNE, SNO, SNP, MSGSN, BSSO, ESPN+, SN NOW).
"It's a huge game," Graves said. "You circle these ones on your calendar. You're looking forward to it.
"Both teams coming in on a back to back. This is going to be a good test for our group. I'm sure they're kind of thinking the same thing."