Cristiano Ronaldo has questioned why he got a yellow card but Morten Gamst Pedersen escaped during Manchester United's Premier League win over Blackburn Rovers.
The pair were involved in contentious incidents at either end of the field during the second half of United's 2-1 home success on Saturday.
But while Ronaldo was booked for diving, referee Howard Webb merely chose to wave play on when Pedersen went down under Rafael Da Silva's challenge.
''I didn't think theirs was a penalty,'' he said. ''The referee did not give it anyway. He didn't give the player anything either - but he gave me a yellow.''
Sir Alex Ferguson was even more forceful in his condemnation of an incident he felt was clear-cut - even if his opposite number Sam Allardyce had a different view.
''It is not a blatant one, but Da Silva has had a little tug,'' argued Allardyce, who refused to rebuke his player for hitting the deck. ''You have to make the referee's mind up - Kevin Davies will tell you that.
''He gets fouled more than anyone else in the Premier League. He stays on his feet and never gets fouls. What do you do?''
The latter incident denied Rovers a point; the former was part of a stormy five-minute period during which Ronaldo might easily have been sent off if Webb had taken a less lenient view of a clash with David Dunn that Ferguson felt was sensible but fears others may not.
''I know people will make a meal of it. But it was no more than a flick, and the referee gave him a warning. You see it time and time again,'' observed Ferguson.
''He has to live with the examination of him. It would have been a ridiculous sending-off.''
Ronaldo is unlikely to be adversely affected by any criticism, especially because he can take the memory of his brilliant match-winning free-kick with him on tomorrow's flight to Milan for the Champions League encounter with Inter Milan.
''I am quite happy with the goal - it was a good free-kick,'' said the world player of the year.
''The manager said it would be a tough game. I am not sure how he knew, but the points are the main thing.
''It is not possible to play beautiful football all the time; sometimes you have to win ugly.''
It is an observation Ferguson has made many times during his illustrious 22-year reign - and having come through such a searching examination, United's bid for an 18th league title only looks more convincing.
However, the full cost of victory will only be seen at the San Siro on Tuesday night when the Red Devils run out to face Jose Mourinho's Inter.
With Gary Neville and Wes Brown already out through injury and Nemanja Vidic suspended, United are desperately hoping John O'Shea recovers from a heel injury that prevented him facing Blackburn - because Jonny Evans seems highly unlikely to be fit, after suffering a recurrence of an ankle problem.
''We are having a nightmare with defenders this season,'' said Ferguson.
''The defenders are being changed all the time. You reach a point when you start to find it hard.''
The changes in personnel, plus a decision to rest Edwin van der Sar in order to prevent the veteran Dutchman having to play three games in six days, might have contributed to Roque Santa Cruz ending United's 14-match record run without conceding a goal.
It was the least Blackburn deserved for their efforts and another reason why Ferguson is loth to take anything for granted, as minds switch towards Champions League combat again.
''There is no way you can predict you are going to win the league when you get games like this,'' he said.
''We have to focus on every game and fight for our lives, just like the teams at the bottom.
''I hope it keeps the spirits up within the squad, because we want to progress in the Champions League - and this is the hardest tie we could have got.''