Cristiano Ronaldo has insisted Manchester United's dream of an incredible Quintuple is still alive as they prepare to take on FC Porto in the Champions League quarter-final.

United boss Sir Alex Ferguson has consistently dismissed his side's chances of ending the season with five trophies as unrealistic - even though they have already collected the Club World Cup in December and the Carling Cup last month.

With his team five matches away from retaining their European crown, top of the Premier League and in the semi-finals of the FA Cup, Ferguson has been anxious not to let the burden of expectation weigh too heavily on his players.

But Ronaldo was far more bullish about United's prospects. The European and World Player of the Year said: "We have the chance to win everything this season. First, we have to beat FC Porto. After that, we must carry on. We are the best team in England, which we have shown by being top of the table.

"We respect all our opponents, but if we carry on winning, we will win the Premier League again."

Ferguson is likely to have breathed a huge sigh of relief when his team were drawn against the Portuguese champions, instead of being paired with Liverpool, Chelsea or Barcelona.

Yet the Scot warned his players against complacency, especially with United's Champions League exit at the hands of Porto in 2004 still fresh in the memory.

That 1-1 draw at Old Trafford is remembered for then-Porto manager Jose Mourinho's celebratory dash down the touchline following his side's late equaliser, and Ferguson acknowledged: "It would be stupid to think this is going to be easy.

"When teams are used to winning their domestic title, as Porto are in Portugal, you always feel they will play with great confidence. They have a lot of South Americans in their team, as well, which gives them great physical strength.

"By beating Atletico Madrid in the last round, Porto proved they will be hard to beat. Complacency does not come into it as far as we are concerned. We will be going at full throttle in order to get the result we want."

Wayne Rooney, Nemanja Vidic and Paul Scholes all return from suspension for the champions, but Vidic's central defensive partner Rio Ferdinand is likely to miss out once more due to a groin problem.

Federico Macheda, the 17-year-old whose stunning last-minute goal on his debut earned United a crucial 3-2 victory over Aston Villa on Sunday, could be involved from the bench.

Meanwhile, international financial services group Prudential has emerged as the favourite to become United's new shirt sponsor.

The club's current £56.5million agreement with the American Insurance Group expires at the end of the 2009/10 campaign. Should Prudential secure a sponsorship deal with United, it is expected to be worth more than £60m to the Old Trafford giants.