Rio Ferdinand: We the fans salute you.....

Football can be a strange game at times, last week Porto were made to look like world-beaters by an abject Manchester United who contrived to put the balance of their Champions League quarter-final tie in favour of the Portuguese club. But what a difference a week can make because following a run of poor performances coupled with some rank bad defending and when many were starting to predict the champions downfall, United look to have turned it around as they went on to win the second-leg in Portugal last night courtesy of a 30-yard wonder striker from Cristiano Ronaldo.

While United have to thank Ronaldo for firing them into a mouth-watering looking semi-final against Arsenal, the man who made the biggest contribution on the night was Rio Ferdinand. The England defender has been out on the sidelines after sustaining a groin injury while on international duty and how United have missed his calming influence at the back.

Some believe that Ferdinand is the world's best defensive interceptor; he snuffs out trouble before it develops into a catastrophe by using his pace and by reading the game. Ferdinand's partnership with Vidic has undoubtedly been at the very heart of United's success this season, when either player has been missing due to injury or suspension the defence has been all at sea.

The contrast between the two United performances against Porto was almost unbelievable. In the first leg, United's defence once again all over the place after Jonny Evans gifted the visitors possession early doors which led directly to a goal - that mistake set the tone of the first leg because it gave a hungry looking Porto encouragement to keep on going forward. For their part United looked to be on course to fall apart due to the team malfunctioning all over the pitch. The first leg ended 2-2 and the general consensus was that United were very fortunate to get anything from the game.

United then faced Sunderland and only just managed to sneak a victory following the late introduction of boy-wonder Federico Macheda, but once again poor defending was a feature of the champions play. It was for good reason that many supporters had a bad feeling about the impending trip to Portugal - if your team struggles against a club haunted by the threat of relegation, then what are your prospects of victory against team like Porto who looked mean and 'up for it' at Old Trafford?

As it turned out last night's game in Porto was relatively trouble free from United's perspective. All of a sudden the defence that has been all too easy to breach looked solid again, as a result Porto were restricted to long-range efforts and a couple of headers. In contrast to the first-leg at Old Trafford, United's defence held firm and the midfield did their job when closing down the space in front of the back four.

Instead of sitting too deeply and allowing Porto to dictate the play, Ferdinand was stepping out of defence and intercepting on the half-way line when making important challenges. In the first-leg, the Hulk was rampant, at times it took two United players to stop his raiding, last night he was reduced to a bit-part player - he couldn't make his presence felt because he had been marginalised along with his team-mates.

At this stage it is impossible to predict how the rest of the season will pan out for United, many fans were starting to have negative thoughts about the challenges ahead, but the win against Porto could see the team galvanised and back on the road to what is still a hugely improbable quintuple.

It would be wrong not to mention the part played by Fergie, who isn't acknowledged as a great tactical thinker, because last night he switched Rooney from the left flank where he played against Sunderland at the weekend to the opposite wing. Rooney had no doubt been detailed to help his fullback stop the Hulk and Cissokho. On the opposite flank, Giggs was brought in partly to deny Porto raiding down that wing. The plan worked a treat.

It was by no means a perfect United performance. Berbatov, while retaining possession quite well at times, all too often the Bulgarian was slow in foot races and on other occasions too easily brushed off the ball.

Michael Carrick's passing was once again wayward at times, which has been a feature of his recent performances, but to his credit he did an excellent defensive job for the team.

Ronaldo's goal needs no in-depth analysis - few players in the world are capable of scoring a goal like that on such an occasion - but it was only his second goal in this season's Champions League campaign, when compared to last season we know he can give a lot more.

Anderson had his best game of the season and was close to being my man of the match, but that accolade goes to Ferdinand who didn't put a foot wrong.

United can and hopefully will build on the win over Porto, but make no mistake it is going to be another very bumpy ride - bring on the Arsenal.