Sunderland manager Sam Allardyce described Liverpool counterpart Jurgen Klopp as "a soft German" after a row over a Jeremain Lens tackle.
Lens was booked for a foul on Mamadou Sakho during the closing stages of Liverpool's 1-0 Premier League victory on Wednesday.
Klopp was unhappy with the challenge and felt Lens should have been sent off at the Stadium of Light.
Allardyce hit back at Klopp and said referee Kevin Friend had taken the appropriate action.
"If he thinks that's a red card, then he's a soft German. It's a yellow, a foul," he said.
"There was some foul and abusive language towards my staff that I didn't like."
Allardyce was responding to the former Borussia Dortmund coach's claims the tackle was definitely worthy of a red card.
Klopp said: "Of course. This is a foul. That is not allowed. For me that is a red card, finished."
Allardyce said he had moved on from the sideline exchange with a handshake at the end of the game.