Rotherham's first pre-season friendly ended in disappointment after a 2-0 defeat by Sheffield United.
Tuesday's game against Leicester at Don Valley was abandoned in the second half after floodlight failure, meaning this was the Millers' first 90-minute run-out.
And they started well, with Adam Le Fondre twice going close in the first half, but the Blades' superiority shone through in the second half and goals from Johannes Ertl and Daniel Bogdanovic gave them the win.
Boss Ronnie Moore again fielded new signings Ryan Cresswell, Tom Newey, Mark Bradley and Marcus Marshall after they made their debuts in Tuesday's abandoned friendly against Leicester, but Johnny Mullins and Tom Elliott both missed out through injury.
Rotherham's pre-season preparations continue when they visit Alfreton on Tuesday.