Stephy Mavididi's late header saw Leicester regain control of the race for promotion from the Championship and condemn relegation-threatened Birmingham to a 2-1 defeat.
Gary Rowett's men appeared on course to claim what would have been a precious point in their battle for survival after leading goalscorer Jay Stansfield cancelled out Kiernan Dewsbury-Hall's opener.
But just as Enzo Maresca's side looked set to pay the price for their profligacy, Mavididi ensured a dominant performance at the King Power Stadium did not go to waste as the hosts climbed back into top spot.
Both under pressure for completely different reasons, neither the Foxes nor the visitors looked overawed by the occasion.
But it was the attacking prowess of Maresca's side which enabled them to dominate the opening exchanges, with John Ruddy making a save to deny Dewsbury-Hall and Patson Daka's pace causing all manner of problems.
Although Blues were losing the battle for territory and possession, they still carried a threat.
Koji Miyoshi tested Mads Hermansen's handling with a low angled drive before the hosts finally engineered a 28th-minute breakthrough. On target for the second time in as many outings, it was Dewsbury-Hall who produced the finish.
But Blues were the architects of their own downfall, failing to clear Abdul Fatawu's cross into the area before Daka touched the ball into his team-mate's path.
Only a tendency to over-elaborate in advanced positions prevented Leicester from establishing a healthier lead before the break.
That came back to bite them in the 45th minute when Hermansen, taking an age to clear his lines after receiving the ball from Wout Faes, saw his kick charged down by Stansfield and fly into the net.
As the hosts regained their
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