Plymouth shrugged off their shock FA Cup defeat at Stourbridge as a first-half goal-blitz saw off Northampton.
Three goals came within the opening 17 minutes for rock bottom Argyle, who ended their seven-match winless run.
Simon Walton converted a penalty after John Johnson's handball and then Nick Chadwick headed a second in his first match since returning to Home Park.
Will Atkinson and Ashley Hemmings made it 4-0 at half-time, before Adebayo Akinfenwa scored a late consolation.
Hemmings joined Plymouth from Wolves on Thursday, while Chadwick moved on loan from Stockport, three years after ending his first spell at Home Park.
Chadwick, making his 50th league start for the Pilgrims, netted his 11th goal for the club with a powerful header from Conor Hourihane's cross.
Atkinson made it 3-0 on 17 minutes when his mazy run ended with an angled shot that flew in past Northampton goalkeeper Sam Walker.
And things would get worse for the Cobblers just before half time when Chadwick set up 20-year-old Hemmings to score his first goal in professional football.
Northampton have now conceded 11 times in their last two matches following a in their last outing, David Lee's only game as caretaker manager.
It was a miserable day for former England goalkeeper Tim Flowers, who was taking temporary control of Northampton for the first time since Lee's exit.
Akinfenwa's late header was no more than a consolation for the visitors, who have not won any of their last eight league matches and are in 21st place in the table.
Plymouth, meanwhile, remain bottom but are now just three points adrift of safety.
VIEWS FROM THE DRESSING ROOM
Plymouth Argyle manager Carl Fletcher told BBC Radio Devon:
"We had a few new faces and I'm really pleased with the result.
"We could have played anyone today and we'd have beaten them.
"I'm really pleased for the lads that have been here all season, its been a tough week."
Northampton Town caretaker manager Tim Flowers tells BBC Radio Northampton:
"We were completely and utterly blown within 17 minutes - run over the top of by a team that's bottom of the table. That's no disrespect to Plymouth, because they murdered us.
"Defensively, out of possession, it was a horrendous performance in the first half. We were second best to everything. It's unbelievable.
"Whoever comes in (as manager), the mission is the keep the club in the league. The Blue Square Bet Premier is littered with clubs like us who've gone and haven't come back."