The formfer Charlton Athletic keeper joined the Blades last week on the same day United captured Andy Gray from Bradford City, but only on a short term contract.
"Paddy has been absolutely brilliant and I'm here to provide him with healthy competition," Ilic told sufc.co.uk. "I am confident and dominant - I am a player who just likes winning.
"There is potential to stay at the club beyond the end of the season, but that will depend on how the club does and how I do.
"If everything goes well then maybe there will be something at the end of the season."