Atletico Madrid vs. Man United: Red Devils hit with fresh double injury blow ahead of Champions League clash

Mainoo played the full 90 minutes of Saturday's 1-1 draw with Tottenham Hotspur in the Premier League, but Shaw was replaced in the latter stages of the contest by Ayden Heaven. Man United had an open training session on Monday morning ahead of their trip to Madrid, and neither Mainoo nor Shaw were present.

According to BBC Sport, the duo are both regarded as major doubts for the clash with Atletico; a final decision is set to be made this afternoon. Benjamin Sesko and Patrick Dorgu will again be absent on Tuesday, while Noussair Mazraoui remains a major doubt for the 20-time English champions.

Shea Lacey, Harry Amass and Jack Fletcher were all present in the first-team session and are likely to be in the travelling squad for the clash with Diego Simeone's side. Carlos Baleba came off the bench to make his Man United debut against Tottenham, and the Cameroon international could now be introduced for his full debut as Mainoo's replacement.

Andrey Santos and Mason Mount are also potential options for the Red Devils in that area. However, it is more complicated when it comes to the left-back spot; Leny Yoro started at right-back against Spurs, and if that is again the case against Atletico, then Diogo Dalot could be introduced into the XI in the left-back role.

Amass is also an option, while Heaven finished Saturday's game at Spurs at left-back.