Jamie Cureton scored his 14th and 15th goals of the season to grab victory for the improving Grecians despite Chris Whelpdale putting the leaders in front with just four minutes on the clock.
Alan Gow struck a 27th minute equaliser then Cureton hit his first in the 54th minute before Danny Jackman equalised for the hosts on 79. Cureton converted a Liam Sercombe cross from close-range to take the points.
Second-placed Port Vale took full advantage, celebrating coming out of administration this week by hammering Bristol Rovers 4-0 at Vale Park. Tom Pope scored a hat-trick and Ben Williamson also got on the scoresheet.
Third-placed Cheltenham were thrashed 4-1 at Chesterfield, for whom Chris Atkinson and Sam Togwell scored to give them the half-time lead. Kaid Mohamed briefly reduced the deficit before the hosts scored further goals through Marc Richards and Jack Lester.
But fourth-placed Fleetwood failed to make the most of their rivals' reversal as they were also surprised 3-1 at home by Accrington Stanley.
Stanley sailed into a 3-0 lead with a James Beattie penalty and further goals from George Miller and Romauld Boco before Jamie McGuire grabbed a late consolation for the hosts.
Wycombe moved off the bottom of the table with an excellent 3-2 win at Rotherham, who had taken a first minute lead through Daniel Nardiello.
Wanderers responded with a Dave Winfield equaliser and a double from Matt McClure, before Mark Bradley gave the home side a glimmer of hope late on.
A fourth minute goal from Dani Lopez proved enough to give fellow strugglers Aldershot a precious 1-0 win at Burton, sending Barnet back to the bottom despite their 2-2 home draw with Oxford.
Jake Hyde put the Londoners in front in the fifth minute but Sean Rigg quickly equalised and Andrew Whing put Oxford in front, only for Hyde's second of the night to take a share of the points.
Southend eased to a 4-0 win at Wimbledon with two from Gavin Tomlin and further goals from Ryan Cresswell and Barry Corr.
Meanwhile Northampton boosted their play-off ambitions by easing to a 3-0 win over Morecambe at Sixfields. Adebayo Akinfenwa, Ishmel Demontagnac and a Kevin Ellison own goal proved enough for the Cobblers.
Plymouth slumped dangerously back towards the drop zone after a 21st minute goal from Gary Jones gave Bradford a 1-0 win at Valley Parade.