Manchester United manager Erik ten Hag was left seething over referee Maurizio Mariani's decision not to send off Barcelona defender Jules Kounde for a challenge on Marcus Rashford.
With United 2-1 up in the 64th minute, Rashford appeared to be bundled over by Kounde when he was racing towards goal but a foul was not given by Mariani and Barcelona equalised through Raphinha in the 76th minute.
Ten Hag was booked for remonstrating with the officials but was strident in his criticism of the referee, the linesman and the Video Assistant Referee for failing to dismiss Kounde for a professional foul.