Teenager Tommy Wright (pictured) was the hero for the Foxes, stabbing home from six yards for the all-important winner eight minutes before the interval.
Mickey Adams's men defended stubbornly in the second period to hold on for a victory which takes them back level on points at the top of the table with Portsmouth.
Elsewhere, Wolves bolstered their play-off hopes with a crucial 1-0 victory at struggling Grimsby.
Welsh international Nathan Blake made up for his weekend dismissal against Rotherham by notching the decisive goal after just 13 minutes.
The former Bolton hit-man slammed home left-footed from 18 yards to hand his side all the spoils, and move them six points clear of Ipswich in seventh place.
Burnley put an end to their recent miserable run with a comfortable home win over Preston North End.
Goals in each half from Dimitrios Papadopoulos and Robbie Blake were enough to see off a lacklustre Preston, and end a run of seven games without victory.
Watford gave themselves the ideal preparation for Sunday's FA Cup semi-final against Southampton with a 1-0 away win at Crystal Palace.
The Hornets made eight changes with the Cup clash in mind, but came out victorious thanks to an own-goal from Palace's David Hunt on the stroke of half-time.
Match summary:
Burnley 2-0 Preston
Crystal Palace 0-1 Watford
Grimsby 0-1 Wolves
Leicester 1-0 Nottm Forest
Click here for an updated Division One table.
