The dramatic late strike moved Celtic to 64 points, just three behind leaders Hearts and two adrift of second-placed Rangers, with the season entering its decisive phase.
Yang Hyun-Jun had given Celtic an early lead in the ninth minute, finishing from close range after Benjamin Nygren’s assist. Dundee, yet, grew into the game and equalised from the penalty spot in the 57th minute through Simon Murray.
Celtic manager responded by introducing fresh legs, bringing on Marcelo Saracchi for Kieran Tierney in the 76th minute and Iheanacho for Tomáš Čvančara shortly before.
The Super Eagles forward then delivered the decisive moment: Saracchi’s dangerous cross from the left flank was poorly cleared by Dundee defender Ryan Astley, allowing Iheanacho to out-muscle his marker, control the ball with his back to goal, spin sharply, and fire a clinical left-footed finish past goalkeeper Jon McCracken from six yards out.