Sir Alex Ferguson has paid tribute to the departing Carlos Queiroz after another difficult day for Manchester United in which the manager lost his right-hand man and it emerged that Cristiano Ronaldo faces an angry backlash from supporters even if he is forced to remain at the club.

Queiroz was confirmed last night as Portugal's new manager, signing a four-year contract, and Ferguson did little to disguise the fact that it represents a considerable blow to his hopes of another triumphant season. "Carlos is one of the best coaches in world football," said Ferguson. "His attention to detail, ability to innovate and will to win have been a key factor to the team's recent successes. He has played an important role in building and blending the exceptional squad of players at the club."

Ferguson could be forgiven for sounding downbeat as he contemplated his problematic build-up to the new season and the possibility that it could get worse before it gets better. Queiroz's departure will inevitably damage United's hopes of pulling Ronaldo back into line and, even if they do manage to keep the footballer of the year from Real Madrid's clutches, it is becoming clear how far he has fallen in the estimation of the fans who used to adore him.

One poll of more than 300 fans on the unofficial Redcafe website has only 11.95% of voters saying he should not be sold. Of the other three categories, 48.74% want him to be transferred, 14.15% say he should be left to "rot in the stands" and 25.16% argue that he is "young and learning" and may, in time, be forgiven.

Ronaldo need only log on to the club's official website and look at the messageboard there to see how much anger and resentment he has caused, not least in his support of the Fifa president Sepp Blatter's view that United's refusal to let the player get his way could be described as "modern slavery".

Blatter, who was made an honorary member of Real Madrid in November 2006, is regarded with extreme suspicion at Old Trafford and Ronaldo's assertion has invited derision throughout the football community. Steve Bruce, the Wigan Athletic manager and a man whose Old Trafford past makes him reluctant to say anything remotely controversial about his old club, summed it up: "If they [footballers] are slaves, what the hell are the rest of us?"

Queiroz, unlike Ronaldo, has always been intent on leaving Old Trafford with his dignity intact and spent yesterday saying his final goodbyes to players and staff at the training ground. The 55-year-old, arguably the most influential No2 operating in the Premier League, will be badly missed, having been entrusted with more responsibility than any of his predecessors in his job,

"Carlos has played a major part in the club's recent success," said David Gill, United's chief executive. "I have thoroughly enjoyed working with him over the last few years. His experience and professionalism have undoubtedly been a key factor in his securing his new role and everyone at Old Trafford wishes him the best of luck in guiding Portugal to the 2010 World Cup."

Queiroz, who will hold a news conference in Lisbon on Wednesday, is understood to have forgone some bonuses to bring down the compensation package that has been hammered out between the club and the Portuguese football federation. "I am very proud and honoured to be able to serve my country," he said last night in a brief statement. "This is a very special position that any professional would want. I also want to thank Manchester United for helping make it possible."

Ronaldo is reputedly one of the Portuguese players who were campaigning for Queiroz to be recruited once it became clear that Luiz Felipe Scolari would take over from Avram Grant at Chelsea.

That in itself will not endear Ronaldo to United's increasingly aggrieved supporters but the player continues to give the impression he is oblivious to the furore he is causing. "He is the perfect choice," Ronaldo said of Queiroz's appointment on Portuguese radio last night. "I have been working with him for some time and I have to say that he is very good for this job."

Who's the new No2?

9-4 Brian McClair United coach

5-2 Mike Phelan United coach

11-4 Rene Meulensteen United coach

9-2 Pako Ayesteran former Liverpool coach

14-1 Ole-Gunnar Solskjaer United coach

20-1 Eric Cantona actor, beach football coach

Odds from William Hill