In time the 2008-09 season will come to be viewed as an added extra to Cristiano Ronaldo's Manchester United career, a hastily agreed option that did not really work out to the entire satisfaction of any of the parties concerned and a contractual obligation that merely delayed the inevitable.

Knowing what we know now, Ronaldo might have been better packing his bags and his Champions League winner's medal at the end of last season and leaving United wanting more. He might even have commanded a higher sum 12 months ago, before the credit crunch kicked in, and he would have found himself the centre of attention as the only galáctico at the Bernabéu instead of having to share top billing with Kaka.

From United's point of view a record-breaking £80m represents good business for a player who clearly wanted to leave. It does not matter what Ronaldo might have gone on to achieve with United, how difficult it will be to replace him or what it actually says on his contract. Once a player has indicated he would rather be somewhere else it is time to stop talking legalese and start talking money.

United did well to resist Ronaldo's attempts to leave last summer, but apart from the two stunning long-range strikes that propelled the team into a second successive Champions League final, they did not enjoy the same sort of enthusiasm and input from a player who finished the previous season with 42 goals. Ronaldo still managed to weigh in with a far from insignificant 26 goals in the season just ended, but it was obvious a parting of the ways would come sooner rather than later and noticeable that Sir Alex Ferguson stopped bristling with defiance whenever the subject of Real Madrid was raised and instead simply claimed he was tired of discussing the matter.

At 24, Ronaldo arguably has his best years ahead of him, although it remains to be seen whether Real Madrid get as much out of him as Manchester United. They will not be getting the same value for money, for a start. The £12m United paid in 2003 looks trifling when set against the trophies, goals and moments of individual brilliance that lit up his six years at Old Trafford, and though a certain petulance and willingness to fall over in search of free-kicks could be entered in the debit side of the ledger, there is no doubt United fans greatly enjoyed watching a precocious teenager grow up to be a world-beater.

One hopes, quite literally, that Ronaldo can keep his feet on the ground in Madrid. He has the talent and the temperament for the Bernabéu, although one suspects if things ever start to go wrong they could go wrong quite badly. One thing Ronaldo is going to have to get used to straight away is more meetings, and more relentless comparisons, with Barcelona's Lionel Messi. The pair have been rivals in the World Player of the Year and Ballon D'Or stakes for the past few seasons with Ronaldo pipping Messi to the awards this season, although there was no doubt the Barcelona player won hands down in the head-to-head contest that was the Champions League final. If that trend continues in La Liga next season, Ronaldo is going to have to prove he can live up to his reputation and his transfer tag.

As for United, they have £80m in the kitty after losing a player they always knew they were going to lose. It is a bit like the George Best scenario but with a world-record transfer fee as compensation. Although Best spent 11 seasons with United, only nine of them could be described as full seasons. Ronaldo gave United six full seasons, took them to three league titles and two European Cup finals and left for £80m. It's good business all round, assuming United can source another tricky winger with the whole of the world to choose from.

The only nagging doubt is that unlike Best, Ronaldo has plenty of time left to come back and haunt them. He is not going to turn up at Dunstable Town, Stockport County or Fulham, after all. If Real Madrid get their act together quickly, with Ronaldo and Kaka linking up, there could soon be two Spanish teams blocking United's path to another European Cup.