Martin O'Neill has hailed the impact made by Richard Dunne since he joined Aston Villa last summer.
The Irish centre-half moved to Villa Park in a £6million deal from Manchester City after it became apparent that opportunities at Eastlands were going to be in short supply.
The Blues invested heavily in fresh talent last year, with the likes of Joleon Lescott and Kolo Toure brought in for big money to help shore things up at the back.
That appeared to push Dunne down the pecking order and forced him to weigh up his options.
City's loss has proven to be Villa's gain, with Dunne having marshalled Martin O'Neill's back four in exemplary fashion, leading to him being named in the PFA Team of the Year for 2009/10.
He is preparing to return to Eastlands for the first time since leaving City this weekend, in what promises to be a crucial contest for both sides, and the 30-year-old will head back to the North West basking in high praise from his current club boss.
O'Neill said: "Richard deserved the reception he got in the game at Villa Park (when he scored in a 1-1 draw). Manchester City would accept he was brilliant for them over eight or nine years.
"Richard Dunne was exceptional for Man City over a long period of time. He became an iconic figure. We are just delighted to have him.
"He has made an immediate impact coming here and he has been a really great signing.
"Richard was voted into the PFA team of the year which was a great boost for him. He would have derived a great deal of benefit and confidence from that."
Both Villa and City remain in the hunt for a top-four finish in the Premier League this season, but O'Neill accepts that his side are outsiders for UEFA Champions League qualification and need to take maximum points from their remaining two games to stand any chance.
He said: "Self belief can't be much higher. We have got over the debacle of losing 7-1 at Stamford Bridge a month ago, have fought back magnificently and given ourselves a chance.
"That is all we could have done from that position we were in. We will go to Manchester City with loads of confidence after taking 13 points from 15.
"We know we have to win and the only way we have been able to do that is going at teams.
"Our away record is terrific. People will say that is because we have pace in the side and are capable of beating teams on the break and I would not disagree with that.
"We are going into the game with confidence and with a chance of winning."