By Amitai Winehouse For Mailonline
Published: 09:16 GMT, 21 January 2020 | Updated: 09:40 GMT, 21 January 2020
The incident followed Roberto Firmino's disallowed goal, when referee Craig Pawson initially did not give a free-kick for what appeared to be a foul by Virgil van Dijk on David De Gea.
The United players surrounded the referee to complain about the decision. It was eventually overturned with the intervention of VAR.