Ifill, who was signed for £800,000 this summer from Millwall has scored three goals in eight games for the Blades since his move.
Paul Ifill: Bargain Buy
"Paul has done very well," Warnock told www.sufc.co.uk.
"People don't know what he's going to do next - his unpredictability has created chances for us.
"I'm pleased he is running at defenders and there is certainly more to come from him. Defenders are paying a lot of attention to him in the way they did to Michael Brown and Michael Tonge a couple of seasons ago."