The Reds must beat the German champions on Tuesday and hope FC Copenhagen and Galatasaray draw their match in Denmark if we are to progress to the competition's knockout rounds.
McTominay, who turned 27 on Friday, is United's leading scorer this season, with his brace against Chelsea taking him to six efforts for the term.
The Scotland international opened his Champions League account last time out, in the helter-skelter 3-3 draw with Galatasaray and he was asked about his recent goal record, as well as the team's apparent lack of consistency and control, by reporters at Carrington.