After nearly 22 years in the Old Trafford hot-seat, back-to-back Premier League titles and a second Champions League win, Ferguson could have been forgiven for thinking the two seasons he has given himself to achieve any remaining ambitions would be relatively stress free.

Instead, the Ronaldo issue that came to light before the dust had even settled on United's penalty shoot-out win over Chelsea in Moscow, is rumbling towards a distinctly unsatisfactory conclusion.

While Ferguson will have no problem sticking to the club mantra of Ronaldo not being for sale at any price, he cannot know what lengths the 23-year-old will be prepared to go to in order to get his wish.

Veiled threats of strike action should United refuse to deal with Real Madrid in the three weeks between Ronaldo completing his stint at Euro 2008 with Portugal and a scheduled return to training have been treated with scepticism at Old Trafford.

United officials believe once Ferguson or his trusted assistant Carlos Queiroz speak to Ronaldo they will have a far better understanding of each other's position.

Certainly any thought Real might get more joy by dealing directly with the Glazer family can be discounted as United's American owners are at one with Ferguson and chief executive David Gill in their belief Ronaldo will remain where he is.

However, any bargaining position will be undermined should Queiroz be courted - and accept - a potential offer from Portugal to replace Chelsea-bound Luiz Felipe Scolari.

Ronaldo could justifiably point out that for Quieroz to preach loyalty, he would need to show some himself and that might not be so easy if his country comes calling, particularly as there can be no guarantee he would be appointed Ferguson's successor no matter how many times the Scot praises him.

Should Portugal's European Championship campaign end at German hands this weekend, Ronaldo would be due back to United's Carrington HQ while his club colleagues are in South Africa on their pre-season tour.

That raises the possibility of Ronaldo being asked to turn out in a fixture at Oxford, where he made his return after the World Cup two years ago.

On that occasion, Ronaldo was jeered by the home fans but praised by his own, offering the first hint that he could overcome the hysteria created by his fall-out with Wayne Rooney.

This time, any adverse reaction could come from Red Devils supporters who have become weary and irritated in equal measure by Ronaldo's posturing.

The smart money would be on the impasse being broken during the intervening period, although at this stage it is difficult to see exactly how.

But Ferguson could certainly have done without the hassle at this stage of his illustrious career and Ronaldo might well be about to discover, even at 66, he is not a man to cross.