Iheanacho who came on as a 62nd minute substitute for Ayoze Perez, provided the assist for Jamie Vardy to draw Leicester level in the 68th minute.
And in the 94th minute, he scored the winner to give the Foxes a hard-fought 2-1 win.
It was Iheanacho’s first league game of the season after only appearing in the League Cup.
“This one is for the fans, the staff my teammates and my family, thank you for been there for me,” he tweeted on his Twitter handle on Monday.
The win has lifted Leicester to the second spot on 32 points, eight points behind leaders Liverpool.