Sheffield United appeared destined to secure all three points when first-half goals from Jamie Murphy and Harry Maguire put Nigel Clough's side in the driving seat.
But the visitors ensured it finished honours-even when Gary Jones and James Hanson pounced after the interval.
The Blades landed the first blow of a pulsating first-half when Murphy claimed his fourth of the season in the eighth minute.
Tony McMahan, finding himself in time and space on the right flank, drove an angled centre across the visitors' penalty box for the former Motherwell winger, ghosting beyond Stephen Darby, to prod home from close range.
Billy Paynter, making his full Blades debut after joining on loan from Doncaster earlier this month, saw another attempt blocked as the home side pressed forward, but not before they had survived a huge scare at the other end.
City's set-piece delivery caused United problems all afternoon and when Hanson saw a powerful header cannon back off the crossbar, only Jose Baxter's superb clearance prevented Carl McHugh from volleying home an equaliser.
As both teams continued to trade chances, Maguire was forced to dart across the pitch when Aaron McLean, City's new signing, threatened to launch a counter-attack before doubling United's lead just before half-time.
Baxter, who later flashed wide from long distance, whipped a corner towards the far post and the centre-half claimed his sixth of the campaign after beating Jones and Jon McLaughlin to head home.
City dusted themselves down and should have reduced the deficit soon after the re-start, but Hanson and McLean both failed to make the most of a cross from Mark Yeates, who had earlier replaced the injured Kyel Reid.
A huge slice of luck enabled Jones to do exactly that when his deflected shot completely wrong-footed Long before the United goalkeeper diverted the City captain's free-kick into Hanson's path as City restored parity.
Stephen McGinn drew a fine reaction save from McLaughlin after being released by Tony McMahon, Maguire glanced wide and Murphy went close as United pressed before Shaun Miller curled just over the crossbar after tempting McLaughlin off his goal-line.