A brace from Eoin Doyle either side of a Gary McSheffrey strike put the table-toppers 3-0 ahead within the opening 23 minutes, but Morecambe - now in the play-off places - staged an incredible comeback to win 4-3, with all their goals coming in the second half.
Kevin Ellison scored the first, Mark Hughes and Jack Sampson added two more and Padraig Amond then headed the winner with four minutes of normal time remaining.
Fleetwood moved up to second after winning 3-1 at Bristol Rovers, with Jamille Matt opening the scoring and then netting again after John-Joe O'Toole's reply, before Jon Parkin struck in stoppage time.
Exeter are third after beating Plymouth 3-1 at home in Saturday's early kick-off, late goals from Alan Gow and Scot Bennett sealing the win after Arron Davies' opener for the hosts had been cancelled out by Luke Young.
The teams dropping out of the automatic promotion places were Oxford, beaten 2-0 at home by Southend courtesy of goals by Conor Clifford and Luke Prosser, and Mansfield, who were hammered 4-1 on their own turf by Hartlepool.
Andy Monkhouse's goal and a Jack Compton double put the visitors firmly in control and after Sam Clucas' penalty gave Mansfield some hope, it was swiftly dispelled by a James Poole strike.
Scunthorpe moved into the top seven after defeating Cheltenham 2-0 at home thanks to strikes early on from Etienne Esajas and late on from Sam Winnall.
At the other end of the table, Northampton remain second bottom, a point adrift of safety, following their 2-0 triumph at AFC Wimbledon, where Lee Collins and Stuart Dallas got the goals.
Elsewhere, Jed Wallace and Bondz N'Gala (two) were the scorers as Rochdale lost 3-0 at Portsmouth, Newport drew 0-0 at Bury, Billy Kee netted twice - one being a penalty - as Burton won 2-1 at Wycombe, who had Charles Dunne sent off and scored in stoppage time through Matt McClure, and York ran out 3-0 winners at Torquay.
Wes Fletcher, Josh Carson and Ryan Jarvis got on the scoresheet for the Minstermen.