Two points from the last three games have seen Fylde’s comfortable 11-point lead at the top of Vanarama National North reduced to six and second-placed Kidderminster have a game in hand.
Fylde went to in-form Nuneaton unbeaten in seven games but a disappointing first half display left them 3-0 down at the break after conceding three in 17 minutes.
And although Bohan Dixon pulled one back, Devon Kelly-Evans wrapped up a shock result in added time.
Manager Dave Challinor handed a debut to defender Jack Cowgill after his deadline day switch from Barnsley, while fellow newcomer Kieran Kennedy had to settle for a place on the bench.
Top scorer Danny Rowe was nearly given a gift in the opening exchanges, when he almost latched on to a poor back-pass from Exodus Geohaghon, but home goalkeeper Tyrell Belford was quickly off his line to clear the danger.
Billy Daniels was the width of the woodwork from breaking the deadlock moments later, when he left fly with a low drive from 25 yards that had Rhys Taylor scrambling across goal, but to the relief of the Fylde stopper the ball struck the foot of the post.
Neither side really got going in the sunshine at Liberty Way during the early stages but a moment of magic from Kelly-Evans almost lit up the first half when he cleverly ghosted past Caspar Hughes but his cross was just out of the reach of Daniels.
Rowe had another chance midway through the half, when he was picked out in the box by Sam Finley and managed to dig out a shot on the turn but it was comfortable for Belford.
Play raced to the other end of the pitch and Nuneaton opened the scoring on 27 minutes.
A long throw into the box was headed into the path of Ashley Chambers at the back post, and although his attempt was superbly kept out by Taylor, Daniels was on hand for the simplest tap-in.
Chambers himself had the ball in the net with the very next attack, after Jordan Nicholson had bundled the ball through a crowded penalty area, but the referee’s assistant deemed the striker offside.
The hosts doubled their lead six minutes for the break, when Geohaghon launched another long throw into the box that his defensive partner Kevin Langmead powered home with his head.
Things went from bad to worse for the Coasters on the stroke of half-time, when Chambers capitalised on indecision between Andy Bond and Cowgill to race through and slot past a helpless Taylor.
Challinor made a double switch at the break, with Matt Blinkhorn and James Hardy replacing Brendon Daniels and Matt Hughes as the Coasters looked for a way back into the contest.
Hardy made an immediate impact, when his miscued strike from a dropping ball almost looped over Belford but the goalkeeper managed to get a fingertip to it and nudge the ball over the bar.
Blinkhorn nodded one straight at Belford as Fylde started to gather some momentum.
Chambers was still looking a threat for the home side and Fylde needed a good save from Taylor when the frontman was played in by Nicholson.
The visitors pulled a goal back after 66 minutes, when substitute Bohan Dixon expertly fired home from the edge of the box with his first touch after coming on a minute earlier.
Bradley took aim after cutting in from the right with 15 minutes to play, though his low strike was wide of the near post.
And Finley too went close when his cleanly struck shot flew narrowly over the crossbar as the minutes ticked away.
The match was put to bed in added time, when Greg Mills’ cut-back was swept home from close range by the impressive Kelly-Evans.
Manager Dave Challinor said sorry to the travelling AFC Fylde supporters for the “woeful” display at Nuneaton.
Challinor said: “I’ll start by apologising to the people who came down to watch us today.
“I’ll take responsibility but we were woeful today. We were awful.
“I suppose the only consolation is that the way we’ve been all season has given us another life after doing that.
“We need to get that game out of our system quickly and that starts tomorrow.
“Their throw-ins caused trouble because we didn’t head the ball.
“Similar to the Salford game (where Fylde lost 5-0 last month), I could hide behind the fact that we needed to make chances defensively and we don’t have a proper back four.
“However, you can’t hide away from the fact that you still need to go in there and do jobs. You’ve got to compete and ultimately there’s only one ball on the pitch.
“Through a lack of desire, of wanting to head the ball, we’ve ended up costing ourselves.
“They are horrific goals again and I’m sick of saying it. It’s not like teams are doing anything fantastic to beat us. They’re simple goals.
“We can try and try, but the penny won’t drop with experienced players out there. No-one took any responsibility whatsoever. Ultimately it falls on me to take the responsibility.”
DANIEL AGNEW & CHRISTOPHER COUGHLIN
AFC Fylde: Taylor, C. Hughes, Cowgill (Dixon 64), Bond, Kennedy, Baker, Finley, Bradley, M. Hughes (Hardy 46), Daniels (Blinkhorn 46), Rowe.
Subs not used: Kennedy, Kay.
Nuneaton Town: Belford, Gascoigne, O’Hanlon, Scott, Langmead, Geohaghon (Penny 46), Kelly-Evans (Thomas 90), Elliott, Chambers (Mills 90), Daniels, Nicholson. Subs not used: Gould, Dibble.
Ref: Matthew Donohue