Zlatan Ibrahimovic is expected to face a retrospective ban for appearing to kick Everton defender Seamus Coleman in the face.
The incident was not noticed by any of the officials at the time, meaning that the Manchester United striker could face action after full-time that would rule him out of upcoming Premier League fixtures.
The Swede had earlier given Jose Mourinho's side the lead in their Premier League encounter at Goodison Park, his lobbed finish just before half-time being confirmed by goal-line technology.
Ibrahimovic has already been shown five yellow cards in his 20 games so far for the Red Devils since joining from Paris Saint-Germain in the summer.
Less than 15 minutes after their collision, Coleman had to be substituted as he was still left struggling.