Just 12 minutes into Sunday's FA Cup Manchester derby, the Etihad Stadium clash was turned on its head when referee Chris Foy elected to show Vincent Kompany a red card.
The Manchester City captain slid in to win the ball in a challenge from Nani, but had dived in with two feet.
The Portuguese winger seemed to be unfazed and continued playing in an attempt to win back the ball, although a number of other Manchester United players, led by Wayne Rooney, instantly started appealing to the match official.
The home fans were furious when play was brought back for a foul, but that was nothing compared to their reaction when an adamant referee instantly pulled out a red card for the defender, who looked bemused.
Replays showed that Kompany had dived in with two feet, which is an illegal offence and according to the laws of the game is punishable with a red or yellow card, depending on how much 'excessive force' has been used.
However, the Belgium international had looked to be in control of his challenge and he did take the ball cleanly and make virtually no contact with the man, suggesting a lesser punishment may have been possible.
Goal.com wants to know what you think about the decision made by Foy, which undoubtedly had a huge impact on how the game panned out, particularly in United's resulting first-half charge.
Is the red card correct because by the letter of the law a sliding two-footed challenge which should be harshly penalised?
Or should the referee have applied some common sense and awarded just a free-kick or a yellow card given the circumstances surrounding the challenge?
HAVE YOUR SAYLet us know your views by voting in our poll and by leaving a comment below. You can also engage with us and other readers on the Goal.com Facebook and Twitter pages. The best comments and the results of our poll will be published in the days ahead.