He has fitted in effectively at his new club and will face his former team-mates for the first time in Monday’s home Premiership clash.

O’Leary said: “I’ve been speaking to Darius and he sounds really good. He sounds like the lad who, when the move came up, said he wanted a change. He felt he needed that change after so many years.

“He had good people looking after him and they felt the same way and I’m glad it has worked out for him because he is a lovely boy with a lovely talent. I agreed with him and felt a change would do him the world of good.

“He’d been coming to the training ground at Bodymoor Heath for 10-11 years and Darius had been going through the same routine for so long and felt he needed to go to a new environment.

“The Manchester City move was a good one for him. It was a good deal all-round for everyone. Darius wanted to go and it suited us as well. Everybody was singing off the same hymn sheet.”

Villa went on to sign Milan Baros from Liverpool for £6m (€8.8m) after Vassell’s departure, with Kevin Phillips having already arrived from Southampton for £750,000 (€1.1m).

O’Leary said: “I didn’t buy Kevin to sell Darius. We bought Kevin because he was a fellow I had been chasing for a few years from his time at Sunderland.

“We brought Kevin in because he would get us goals. Then, after that, an offer came in for Darius. Darius felt he wanted to go and I felt it was right for him as well.”

O’Leary knows the threat Vassell can cause with his explosive pace but felt his finishing was the one area which could have been improved during his time at Villa.

He said: “People have kept asking me since I came here ‘Is Darius going to score more goals?’ so that’s the thing you want to see him do, score more goals, but he is a big threat for any defence.”

Defender Aaron Hughes will return after resting a groin problem in the midweek Carling Cup win over Burnley but striker Milan Baros is still sidelined with his Achilles injury, although he is back in light training.