Three goals in seven first-half minutes sealed the outcome before Dean Moxey put the gloss on the scoreline with a fantastic goal in the second half.
For Crawley, who have the threat of a ten-point deduction as punishment for slashing player wages earlier in the season, this was one of those nights.
With the home side out of the playoff race following a post-Christmas slide in fortunes, the hosts took an early stranglehold on the match. But the complexion of the match could have been different had Danny Ekoku not fluffed a glorious chance to break the deadlock midway through the first half.
Crawley were left to regret that miss as the hosts took a firm grip on the game thanks to a three-goal blitz before the break.
Jamie Mackie produced a burst of pace to outstrip Ben Judge before stabbing home at the second attempt after keeper Phil Smith had touched away his initial effort.
The Grecians opened up a two-goal cushion four minutes later, Craig Farrell whipping over a corner and Daniel Seabourne powering home his first for the club with a decisive header.
It got even worse for the shell-shocked visitors when Farrell cut inside and let fly with a shot that skidded under the despairing dive of Smith.
To their credit Crawley almost grabbed a lifeline on the stoke of half-time, but Robbie Kember was denied when Martin Rice touched away his rasping drive.
Even though the fizz had been taken out of the contest at the beginning of the second half, Crawley might have fallen even further behind had Smith not taken the sting out of Farrell's drive.
At the other end Rice was performing similar heroics, pulling off a magnificent save to thwart Neil Jenkins, with Danny Woodards on hand to block the rebound.
Crawley's misery deepened when they conceded a fourth shortly after the hour. Moxey raced on to Mackie's throw and after lifting the ball over the advancing Smith kept his cool to guide the ball home from an acute angle.
Crawley knew it wasn't their night when they spurned another opening, this time Lee Blackburn watching in horror as his point-blank drive was somehow saved by Rice.