Leeds lost 1-0 at the Stadium of Light, as Sunderland knocked them out of the FA Cup thanks to a first-half strike from Patrick van Aanholt.
But the Yorkshire side's manager feels the Black Cats struggled after the break, with Austin and Murphy in particular impressive against them.
"I thought we played really well. Second half I thought we were the better side, we turned it into a cup tie," Redfearn told reporters after Leeds' cup defeat.
"There were good performances wherever you looked. If you play well, you get in. That's got to be the message.
"Austin & Murphy bossed the midfield after the break and Sunderland struggled."
Austin has been linked with a move away from Leeds this January, with fellow Championship side Millwall said to be interested in signing the 29-year-old, while Brighton and Hove Albion have also been linked.