Sir Alex didn’t see the match but sympathised with the officials who missed the incident.
“When you play a game of football you always hope you don't get a bad break against you,” he said. “In the modern game, though, with the speed of the game, you could cherry pick every week and look at incidents that should or shouldn't have been penalty kicks, for instance.
“Things happen so quickly for the referee and their assistants. The other night when Demba Ba went through for Chelsea and challenged the goalkeeper he was booked [for diving].
“I couldn't see how that was possibly a yellow card, but that's a decision the referee has to make in a split second. He doesn't have the benefit of replays. Everything happens so quickly so it's hard to make the right decisions all the time.
“I didn't see the Mansfield game, so it's difficult to say if Suarez’s handball was deliberate or not. The lad is laden with controversy and... I don't know if he enjoys it or not, but we hope we don't suffer ourselves on Sunday.
“We want a good game on Sunday. Over the years United-Liverpool games have been relatively free from controversy, to be honest with you. No sensational decisions have marred the game and I think that's good. We've got the two most successful clubs in the country and you hope it's a good game.”