Nigel Pearson's men needed a 90th-minute Chris Wood winner last week against Yeovil Town and, despite the boost of victory over title rivals Burnley at the weekend, required a late goal again at the DW Stadium.
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After Ivan Ramis opened the scoring, Andy King levelled just four minutes before the interval. Rob Kiernan then restored the hosts' lead before Dean Hammond headed home with three minutes remaining to salvage a draw.
The result leaves Leicester seven points clear of Burnley at the top with seven games remaining, while Wigan remain firmly in the play-off shake-up.
Elsewhere in the Championship there was a six-goal thriller at Ewood Park as Blackburn Rovers and Brighton and Hove Albion shared the points following three goals in the final 11 minutes.
Reza Ghoochannejhad grabbed the only goal in a 1-0 win for Charlton Athletic at Elland Road that piled further misery on Leeds United, for whom usually reliable goalscorer Ross McCormack missed a penalty late on.
It was a case of missed opportunities at the top of League One as both leaders Wolves and second-placed Brentford were held to goalless draws.
While Brentford came unstuck against play-off hopefuls Sheffield United, Wolves surprisingly failed to beat Stevenage, who climbed off the foot of the table courtesy of the point they gained.
Thanks to Coventry City's 0-0 draw with Bradford City, the only goals in England's third tier on Tuesday came at Vale Park.
Strikes from Billy Knott and Doug Loft helped Port Vale come from a goal down to edge Crawley Town in a game that saw both sides finish with 10 men.
Bury kept Bristol Rovers in the League Two relegation mix with a 2-1 victory - Hallum Hope and Tom Soares on target for the victors at Gigg Lane.