Speaking about the incident, Martinez said: "There was nothing wrong with McArthur's challenge. He tries to win the ball. But I've seen Mulumbu's reaction given as a red card. It's not a sportsman's behaviour.
"Obviously you expect the ref to be strong and punish Mulumbu.
"Boyce has tried to get in between Mulumbu and McArthur, and Thomas just grabs him. I thought the whole thing was handled by the ref a bit light-handedly.
"But we were so dominant we didn't need that to go our way to win."
Latics supporters were left asking the question if Mulumbu would have been sent off had he reacted in a similar way against one of the big clubs.
