The 24-year-old Nigeria international's 10th Premier League goal of the season -- and 17th in all competitions -- secured a 2-1 win for the Foxes against Crystal Palace on Monday.
He has now scored more goals in the top-flight this season than he managed for Leicester over the previous three campaigns.
Leicester, who suffered the agony of missing out on the top four on the final day of last season, now have a seven-point lead over fifth-placed West Ham with just five games to play.
Iheanacho and Vardy only started eight games together last season and did not do so this campaign until February 28 -- due to injuries to other players, including James Maddison.