Crawley Town substitute David Hunt's last minute own goal gifted Yeovil Town their first victory this season against top six opposition in npower League One.
On an evening when a heavy pitch and inconsistent refereeing often had an overbearing impact on proceedings, just one strike was necessary to settle the tie.
However, the Glovers would have been content with a point until Hunt powered home Jamie McAllister's corner with injury time looming.
With Aston Villa loanee Daniel Johnson returning to his parent club ahead of schedule, Keanu Marsh-Brown returned to the Yeovil starting line up on the right wing with Joe Edwards in central midfield.
Reading youngster Gozie Ugwu was named on the bench but Reuben Reid missed out through injury.
Barely ten seconds were on the clock when Jamie McAllister ducked under a long ball, allowing Gary Alexander to nip in and thump over.
On three minutes Joe Edwards released the lively Marsh-Brown but keeper Paul Jones tipped away his angled shot before Luke Ayling headed wide at the following corner.
Seven minutes later McAllister was left flatfooted by Billy Clarke's flick that found Nicky Adams racing into space. The Glovers skipper recovered to block Clarke's subsequent shot before Korey Smith got in the way of Alexander's follow-up.
Marek Stech's poor save from Michael Jones on 21 minutes gave Clarke a sight of goal but the keeper did well to save before the striker again dragged wide when Yeovil could not clear.
On 23 minutes Dan Burn and Byron Webster were rooted to the spot as Clarke nodded on for Alexander, who snatched at his shot and sent the ball rocketing into the car park.
Fine tackling from Edwards regained possession after 32 minutes and gave him a sight of goal but Paul Jones saved a sharp near post drive.
Four minutes later Marsh-Brown picked out Paddy Madden with a sublime cross but the Irishman fired straight at Paul Jones when a yard left or right would have seen him score.
Ten minutes after the restart Marsh-Brown went for goal from a central free kick but having got the ball powerfully up and over the defensive wall the effort failed to have enough dip to trouble Paul Jones.
Alexander rifled a near-post volley wide on 58 minutes before McAllister charged down Michael Jones' shot when Stech acrobatically punched a corner three minutes later.
On 65 minutes a similar Crawley set piece was allowed across goal and Webster denied Mark Connolly on the line.
Ayling's pressure on Adams was enough to induce a slip with the wide man clean through on 68 minutes.
The midfielder's 72nd minute cross was only half cleared by Yeovil and Ayling gallantly blocked on the line when Josh Simpson's deflected effort threatened to break the deadlock.
Burn was left bellowing in anger at Marsh-Brown nine minutes before time when the defender thought Crawley crossed too easily. Simpson had hooked towards goal and the bouncing ball hit the top of the crossbar.
But the visitors would have the final decisive say, when Hunt - brought on for Kyle McFadzean two minutes before the half - beat Paul Jones under pressure from Madden at McAllister's 90th minute corner.
Crawley Town (4-4-2) - P. Jones; Byrne, McFadzean (Hunt, 43), Connolly, Sadler; Adams, Akpan, Simpson, M. Jones (Ajose, 76); Clarke, Alexander. Unused subs: Torres, Bulman, Akinde, Wassmer, Kuipers.
Yeovil Town (4-4-2) - Stech; Ayling, Webster, Burn, McAllister; Marsh-Brown, Edwards, Smith, Foley (Ugwu, 68); Madden, Hayter (Williams, 80). Unused subs: Stewart, Haynes-Brown, Hinds.
Goals: Hunt og 90.
Bookings: Burn (deliberate handball), Foley (foul), McAllister (foul).
Ref: Andy D'Urso (Essex).