Liverpool-supporting Crystal Palace midfielder Will Hughes was seen shushing Manchester United's supporters after his opponent Casemiro was sent off on Saturday.
The former Watford star also held up six fingers to the home fans after the Brazilian's red card gave Palace an opening back into the game. The number is a reference to the number of Champions League titles won by the Anfield club.
United were comfortable at 2-0 up when their number 18 saw red for his part in a brawl, and the 10 men eventually held on for a 2-1 victory. Referee Andre Marriner missed the incident in real-time, but brandished the red card after the video assistant referee called him over to watch a replay on a pitchside monitor.
