Comeau gave the Stars a 2-1 lead at 15:47 on a rebound from the slot. Janmark threw the puck toward the net, and Comeau scored his sixth goal.
"I dumped it in and [Radek Faksa] did a great job of winning the race to the puck," Comeau said. "He came around the net and gave it to [Janmark], and I just tried to go to the net. I actually thought [Janmark] was going to shoot and he made a great pass. I'm not sure if it went off of my skate or my stick, but I saw it pop out there and slid it home."
The Predators challenged for goaltender interference, but the goal stood following a video review.
Janmark extended the lead to 3-1 at 16:30 on a rebound from below the left face-off circle. It was his fourth goal.
"Absolutely, it gains confidence," Stars defenseman John Klingberg said. "We're still building on something here. Defensively, again, I think we're doing a good job, and obviously the goalies are playing really good as well. Khudobin was real good today, so we'll just keep building here."
Jarnkrok gave the Predators a 1-0 lead at 9:35 of the first period on a wrist shot from the right face-off circle for his ninth goal.
Tyler Seguin tied it 1-1 at 11:11 on a one-timer off a pass from Alexander Radulov. It was Seguin's 21st goal.
"I don't think our start was good," Khudobin said. "We need to find a way to start a back-to-back on the road better, but as the game goes on we kept the intensity better and better. I think we had more legs in the third period, I would say, and we got the result."