Cooper was back in the Leeds team on Saturday afternoon for the visit of Southampton to Elland Road in the Premier League.
He completed the full 90 minutes as the game ended in a draw, with Jack Harrison striking for Leeds in the first half and James Ward Prowse levelling for the visitors in the second half.
Former Whites defender Kilgallon was keeping a close eye on Cooper throughout the game and admits that he noted the defender blowing early on.
However, he feels Cooper put in a superb display in central defence alongside Diego Llorente, which was not easy given he was returning to the side.
“I thought he was really good. It’s tough to come in and play that well”, Kilgallon said post match on BBC Radio Leeds.
“He’s been out a long time, surgery and come in and it’s like he hasn’t been away.
“I watched him for the first 15 minutes with a close eye and I could see him, he was blowing, but that’s because he hasn’t played for such a long time.
“But then he got into it and he was brilliant.”
Leeds’ point has given them further breathing space over the bottom three, with both Burnley and Watford suffering defeats, against Manchester City and Liverpool, respectively.
