Newcastle winger Jacob Murphy trolled Southampton defender Duje Caleta-Car during their Carabao Cup semi final first leg.
The Croatian was sent off for a second yellow card in the game, which the Saints lost 1-0 at home.
Caleta-Car got the second yellow for a shove on Bruno Guimaraes, which resulted in a mini-brawl between the two sides.
As he got his marching orders, Murphy appeared to taunt him by waving and smiling at his face as he walked off the pitch.
Caleta-Car looked furious with Murphy, but did not react as he came off the field.
Newcastle held on for the win and will take a 1-0 lead into the second leg at home.