Kevin Keegan believes Manchester City have unearthed a defender capable of being better than Nemanja Vidic in fellow Serb Matija Nastasic.
The 20-year-old has been one of the stand-out performers for City this season and seems certain to partner skipper Vincent Kompany in central defence for Sunday's FA Cup semi-final with Chelsea.
Keegan has certainly been impressed with the £12million signing from Fiorentina.
"I really like him," said Keegan. "He has come in and played as if he has been there for ever.
"That Mancini put him in for his debut against Real Madrid in the Bernabeu tells you everything you need to know about him.
"In five or six years time you could see him developing into a Vidic. He could become even bigger than Vidic, who has probably been the best centre half in this country for the last five or six years.
"The big test will come next season when people have had a good look at him. They will try and find out what he is not good at and where his weaknesses are.
"I haven't seen too many at the moment."
Nastastic is the one positive from Roberto Mancini's summer signings, with Maicon, Javi Garcia, Jack Rodwell and Scott Sinclair all failing to have the impact anticipated.
That poor recruitment policy is one of the reasons why Mancini's tenure as City boss is said to be in question, even though he was responsible for ending a 35-year trophy drought when he won the FA Cup in 2011 and followed that up with last season's momentous Premier League title triumph.
"In any other sport it would be ridiculous to question someone who has gone into a football club, won the first trophy in 30-odd years, then won the league in the most exciting season ever," said Keegan, speaking at the Soccerex Conference in Manchester.
"Europe was a disappointment. But Europe was disappointing for Manchester United and Chelsea. You get that.
"You can make stories around them all you want. Is it right? No. Can it happen? Yes.
"The media can say that it hasn't worked because he bought five players and they didn't win the title. That looks like they've taken a step backwards.
"But some of those players might be a lot better next season.
"I don't think there should even be a question of anything happening to Mancini."