The Nigeria international’s double was not enough to help the Foxes claim victory over the Millers at the New York Stadium.
Kelechi Iheanacho scored both goals for Leicester City in their 2-2 stalemate with League One side Rotherham United in a pre-season game on Saturday.
After ending his 11-month goal drought against Cambridge United on Tuesday, the forward continued with a brilliant performance at the New York Stadium.
The 22-year-old Nigerian international put the Premier League side in front with his well-taken effort inside the area in the 11th minute.
Carlton Morris brought the Millers back into contention with his 38th-minute strike before Iheanacho restored the lead for his side.
The former Manchester City forward beat onrushing Rotherham goalkeeper Daniel Iversen before he left-footed his effort into the top corner in the 71st minute.
Michael Ihiekwe then scored in the 81st minute to deny the King Power Stadium outfit victory in the encounter.