Blues were cruelly denied the points at the King Power Stadium following a a dramatic end to this Sky Bet Championship fixture.
Matt Green had handed the visitors the lead with his first league goal in the 12th minute after turning home Shane Ferguson's excellent left wing cross.
However, despite a thoroughly excellent display in all areas of the park, the Blues backline eventually gave way with superb and similar strikes from distance form Jamie Vardy and Andy King in the 78th and 82nd minute.
David Nugent rubbed salt in the wound with a penalty in injury time, after Kyle Bartley had been adjudged to have fouled Lloyd Dyer, while Blues sub Chris Burke snatched a stunning consolation with virtually the last kick of the game.
Battling Blues led for 66 minutes and were thoroughly deserving of at least a share of the points after this impressive display against a dangerous Foxes side.
The hosts came firing out of the traps and Darren Randolph had to be alert to make a fine and brave save to deny Vardy in only the second minute; the Irish goalkeeper picking up a hand injury and lengthy treatment for his troubles.
Despite the Foxes bright start, it was Blues who edged into the lead. A wonderful delivery from Ferguson found Green yards out and he made no mistake. It was the former Mansfield man's first Football League goal having chalked up 99 in the non-league game.
Vardy was Leicester's main threat but despite a series of flurries into the visitors' box, Leicester couldn't find a way through before the break.
Once again, Leicester made a storming start to the second-half with interval changes Lloyd Dyer and Anthony Knockaert at the centre of the action. Knockaert, Nugent and Vardy all went close before Blues suddenly went into the ascendancy.
Neal Eardley had Kasper Schmeichel desperately scrambling twice in succession with a directed free-kick and then a cheeky attempt from a corner from the left. Wade Elliott then picked out the rising head of Tom Adeyemi only for Schmeichel to make the save.
Then came Leicester's breakthrough in the 78th minute. Vardy drifted in from the left before sending in a deflected effort beyond the reach of Randolph into the bottom right corner.
Elliott almost struck back immediately for Blues when his low drive from 20 yards flashed past Schmeichel's right hand post.
However the bottom right corner of Blues' net was bulging again. King bringing down a ball from the right before brilliantly picking his spot.
Nugent then put the result beyond doubt for Leicester in injury time. Dyer went tumbling from a Bartley challenge allowing the ex-England striker to send Randolph the wrong way from 12 yards.
Burke ensured that there was some small reason to cheer for the Bluenoses already heading for the exits when he cut in from the right to send an excellent left-footed effort home from the edge of the area.