Erat scored with 22.2 seconds left to give Nashville a 6-5 victory over the slumping Ottawa Senators on Thursday night.
Dumont got his fourth point of the game on the play as he stripped the puck from Ottawa's Dean McAmmond and fed it to Erat, who beat Martin Gerber from the slot for his third point of the game.
Senators captain Daniel Alfredsson had drawn Ottawa even for the fourth time in the game just 23 seconds earlier with his 17th goal.
"There was no panic, actually," Dumont said. "All game long we tried to keep our composure on the bench and it worked pretty well for us tonight. Of course, if we do that too many nights, we're going to get burned. Tonight was just a big two points."
Ottawa has lost five straight games. After racing to a 15-2 mark, the Senators are 1-4-2 in their last seven games.
"It's tough, but that's part of the game," Alfredsson said. "Right now I think we're not playing great defensively and we're maybe too cautious at times instead of being a little bit more aggressive in our own end and getting rid of the puck a little bit too early because we just want to get it out. That's what happened on the last goal and that's what happens when you're pressing a little bit. They made a great play."
Dumont assisted on first-period goals by defensemen Dan Hamhuis and Greg de Vries before he scored his seventh of the season late in the second to give Nashville its third straight one-goal lead.
After Dany Heatley's 13th goal drew Ottawa even for the third straight time 2:47 into the third, Ryan Suter answered 1:03 later with his third goal of season to put the Predators up 4-3.
Suter assisted on Martin Gelinas' third goal that gave the Predators a 5-3 margin at 8:39.
Senators center Jason Spezza made it a one-goal game once again three minutes later with his fourth goal at 11:39.
"It was very nerve-racking, from a coach's standpoint," Nashville coach Barry Trotz said. "You've got a two-goal lead in the third period, you've got to hang on to the game there."
Nashville backup goalie Dan Ellis survived the blown leads to maintain his perfect record with his fifth win in five starts.
"Their top line was gunning and so was ours," Ellis said. "Every single line seemed to not take the night off tonight and I think the fans got a great game and whoever was watching, I hope they enjoyed that one because that was NHL hockey."
Hamhuis scored his second goal of the season on a power play 44 seconds in when he jumped on Gerber's fat rebound of Dumont's shot and put the puck into an open net.
Corvo tied it midway through the first when he moved along the blue line from the left side to the slot and drove a slap shot over Ellis' glove into the top of the net.
Nashville recovered the lead at 16:37 on de Vries' first goal of the season.
Vermette pulled the Senators even once again at 2 when he scored his fourth goal by putting the puck into the net after a rebound of Randy Robitaille's point shot at his feet in the goalmouth to the left of Ellis.
Dumont gave Nashville its third one-goal lead at 3-2 with 1:28 left in the second. Erat carried the puck behind the Senators' net and set up before making a pass to the slot, where Dumont put a quick shot past Gerber for his seventh goal.
Senators defenseman Anton Volchenkov left with a hand injury early in the first. He did not return. ... Right winger Brian McGrattan was a healthy scratch for Ottawa.
Copyright by STATS LLC and The Associated Press
Arena: Canadian Tire Centre Location: Ottawa, Ontario
Referees: Eric Furlatt, Marc Joannette Linesmen: Andy McElman, Derek Nansen
Attendance: 19,538 (105.6% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Dan Hamhuis (2)
(Power Play) Assist: J.P. Dumont
Joe Corvo (3)
Assist: Nick Foligno
Greg de Vries (1)
Assists: J.P. Dumont, Jason Arnott
Antoine Vermette (4)
Assists: Randy Robitaille, Chris Phillips
J.P. Dumont (7)
Assists: Martin Erat, Jason Arnott
Dany Heatley (13)
Assists: Dean McAmmond, Christoph Schubert
Ryan Suter (3)
Assist: Martin Erat
Martin Gelinas (3)
Assists: Jordin Tootoo, Ryan Suter
Jason Spezza (4)
Assists: Wade Redden, Daniel Alfredsson