Champions League Group F/Manchester Utd v Benfica: Alex Ferguson could be forgiven if he was feeling slightly edgy before Benfica's visit to Manchester United tonight, and irritation about being sidetracked by Cristiano Ronaldo's latest diving controversy spilled over yesterday into a classic Ferguson rant about the player's critics, most notable for his description of the Middlesbrough manager, Gareth Southgate, as "very naive".

His temper pricked by Southgate's assessment of Ronaldo as a cheat, Ferguson was puce with anger as he went on the attack, claiming his player was treated unfairly by referees, victimised by the press and totally innocent of all diving charges.

As a committee member of the League Managers Association, Ferguson had been opposed to Southgate's appointment on the ground that the former England defender did not have the necessary coaching qualifications and yesterday he spoke about him in the condescending way a manager talks of an unruly teenager.

"Gareth Southgate's very naive, of course," said the Premiership's oldest manager. "He's just a young manager. We'll have to give him a chance to settle in."

Ronaldo had been accused of diving to win a penalty, giving United a 1-0 lead in the Premiership leaders' 2-1 win at the Riverside Stadium on Saturday. Television replays proved he was not touched by Middlesbrough's goalkeeper, Mark Schwarzer, but Ferguson's argument was that Ronaldo was being persecuted for his behaviour in Portugal's World Cup quarter-final victory against England.

"I've looked at the penalty incident a million times and there is no way a player is going to give up an opportunity to score into an empty goal," said United's manager. "For me it's a clear penalty. But you (the press) have had it in the papers for the last three days, with comment pieces from everyone you can think of. I hope I'm wrong but I have a feeling it's the revenge of the English press. I think you've been waiting for months to do this."

Ferguson has admitted in the past that Ronaldo goes to ground too easily but he said that was no longer the case and that, travelling at speed, there were bound to be times when the player lost his balance. "Cristiano is the most fouled player in the country. All your statistics will tell you that. We played Manchester City last season and there were two career-threatening challenges on him before he was sent off for his own frustration. The first thing that happened on Saturday was that he was hacked from behind and the referee (Chris Foy) did not book the player. Which just encourages opponents to keep kicking him and kicking him.

"And what is more serious in our game: preventing the best players from playing, or going on for three days about a dive that isn't a dive?"

Ronaldo was sitting to Ferguson's right and when the Portugal winger was asked whether the controversy bothered him he simply shrugged his shoulders and said: "No." Pressed further, he said: "The people in England criticise me for anything I do. They love that. Since the World Cup I have just tried to do my best. If I'm criticised by somebody else, I really don't care."

Of Southgate, Ronaldo said: "He stopped playing only last year and in my opinion he should understand football much better."

Ferguson is angry partly because the debate has come at a time when he wants his players to be completely focused on ensuring they survive what promises to be a tense night at Old Trafford. Having won their first three Champions League ties, he admitted he had never anticipated that his side would go into the final game of Group F still needing a point to qualify and he spoke of his shock that losing at FC Copenhagen and Celtic had put them in such a precarious position.

"It seemed as good as in the bag but suddenly we are under real pressure because Benfica have the incentive of knowing a win will take them through at our expense. They have everything to play for. As I say, I can hardly believe it has come to this, although it's absolutely no use bemoaning our position."

There are parallels to be drawn with United's exit from the competition at the hands of Benfica last season, although this time they have home advantage and are going into the match in much better form.

"I know we will do it," said a reflective Ferguson. "But why do my players take us right to the very edge so often?"