Man manager David Moyes has admitted he has missed working with Wayne Rooney.
When Rooney left Everton in 2004 amid some rancour, Moyes could have been forgiven for not being too worried if he ever saw the striker again.
But time has helped heal further damaging statements by Rooney over his relationship with the Scot in his autobiography and after Moyes succeeded Sir Alex Ferguson in the summer, he made it his number one priority to keep the England forward.
Not only did he achieve that, Moyes has been hearing Rooney make the first conciliatory statements since all the rumours started about a potential summer move to Chelsea.
Sir Alex Ferguson stepped into the breach on Thursday, praising Rooney for his outstanding midweek display against Bayer Leverkusen in the Champions League, when the 27-year-old became only the fourth player in United history to score 200 goals for the club.
Now Moyes will look for Rooney to deliver in Sunday's Manchester derby, admitting he is delighted the pair have been reunited.
"Have I missed him?" said Moyes.
"At the time when he left I wasn't too sure but now I am with him I certainly have because he is some player.
"If I had had him at Everton, on several occasions at different times, undoubtedly we would have finished in a much higher position.
"He has matured, as young men do. Once you get a family it calms you down."
Although some argue otherwise, Moyes feels Rooney has developed into the talent he seemed destined to become when he first broke onto the scene as a 16-year-old in 2002.
"He was always a great player," said Moyes.
"Even when he was leaving Everton he had the potential.
"He had all the ability in the world but could he pull it all together?
"He has proved that over many years.
"He can lead the line, take the ball in, play two or three positions and score lots of goals."
And almost as importantly, Rooney is fully fit, returning for pre-season training in far better shape than any time in the recent past.
"The big thing is he got himself into really good shape physically," said Moyes.
"Just before he damaged his hamstring in Thailand - I told you that but I don't know if you all believed me.
"I was really impressed with the condition he was in. He looks lean. He is back to being his aggressive self again. He is fast and hungry.
"I needed all those things from him if I was ever going to get Wayne back to the level he is at."
And for that, Moyes gives credit to just one person.
"Everything he has done he has done himself," said Moyes.
"He has knuckled down really well and done his training.
"Now he is getting the fruits of that but don't for one minute think I am going to take the credit."
Inevitably therefore, talk has already turned to the possibility of securing a new contract for a player whose present deal now has less than two years to run.
There have been suggestions Rooney will buy himself out at the end of the season, effectively pay a lump sum to United in order to make himself a free agent.
His recent performances suggest an alternative ending to this long-running story although Moyes is more interested in what happens on the pitch.
"We just go step by step," he said.
"If Wayne could score another two goals at the weekend that would be the next step forward wouldn't it?
"He's played really well and we want him to maintain that.
"If anything, I'm asking him to step up again because I want him to keep getting better."
Rooney will certainly be required at the Etihad Stadium, where Moyes has an excellent record, winning on four of his last six visits with Everton.
There are unlikely to be many changes from the team that defeated Leverkusen, although Ryan Giggs, who was not involved against the Germans, could feature.