The Blades went 3-0 behind through goals from Will Grigg, Haris Vuckic and Chris McCann doing the damage.
But the visitors sparked into life in the last 25 minutes, Matt Done bagging a brace either side of Billy Sharp’s smart header.
A point propels Nigel Adkins’s men to seventh in the League One table, just three points off the play-off places.
In a frantic start the hosts had an early shout for a penalty, the ball seeming to strike John Brayford’s arm in the box, but the referee was uninterested.
Sharp blasted over as the ball broke on the edge of the box, but four minutes later Wigan went in front through Grigg’s expert finish with the outside of his boot.
Newcastle loanee Vuckic made it two just before the break, heading home his first Wigan goal from close range after a quality delivery from Jason Pearce.
Jose Baxter and Sharp both went close after the break, but just as the Blades looked to be growing into the match, McCann converted from close range to further extend the home side’s advantage.
Then came the comeback. Ffirst Done popped up for a simple tap-in, and 15 minutes from time Sharp stole some space in the box to nod home and reduce the arrears to a single goal.
With two minutes to play Done had one ruled out for offside, but just a minute later he netted the equaliser to finish off an amazing fightback for the Blades, playing their first game since the FA Cup exit to Manchester United on Saturday.
Wigan Athletics: Jaaskelainen, Daniels, Pearce, Barnett (James 80), Morgan, McCann, Vuckic (Wildschut 62), Perkins (Cowie 65), Power, Jacobs, Grigg. Unused substitutes: Kellett, Davies, Nicholls, Hiwula-Mayifuila.
Sheffield United: Long, Brayford, Collins, Edgar, McEveley (Woolford 78), Flynn (Adams 78), Basham, Hammond (Campbell-Ryce 88), Baxter, Sharp, Done. Unused substitutes: Howard, Sammon, Reed, McGahey.
Referee: A Woolmer.
Paul Dummett snatched a precious point for relegation-threatened Newcastle as Manchester United twice squandered the lead to draw 3-3 at St James’ Park.
The full-back drilled home a 90th-minute equaliser after Wayne Rooney’s double and a Jesse Lingard goal looked to have claimed the points for the visitors. But Georginio Wijnaldum and Aleksandar Mitrovic netted for Newcastle to set-up the finale.