New footage has emerged showing Rasmus Hojlund's bemused reaction after Kobbie Mainoo was subbed off in Saturday's 1-1 draw against Burnley.
The United striker endured a difficult game at Old Trafford as Erik ten Hag's Premier League woes continued and was brought off by his manager late in the second half.
Hojlund - who joined in a £72m summer transfer from Atalanta - has forged a strong relationship with Mainoo and fellow United youngster Alejandro Garnacho during his debut campaign at the club.
The Danish star has been on of Ten Hag's biggest supporters as the United manager attempts to keep his job for another season, but appeared confused as his team-mate Mainoo was brought off.
Footage taken from inside Old Trafford shows Hojlund walking around the edge of the pitch after being replaced by Amad Diallo, with Mainoo also being withdrawn in the 65th minute as well for Scott McTominay.
Rasmus Hojlund cut a bemused expression as Kobbie Mainoo was subbed off against Burnley on Saturday
Mainoo (right) was brought off by Erik ten Hag (middle) alongside Hojlund in the second-half
Hojlund's international colleague, Christian Eriksen, kept his place in midfield and there was evident frustration inside United's stadium as the double change took place.
Boos later rang around Old Trafford at full-time as Zeki Amdouni converted from the penalty spot late in the game after a mistake by goalkeeper Andre Onana.
Hojlund was walking back to the dugout when he spotted Mainoo's name go up on the fourth official's board and gave an unhappy shake of the head while pursing his lips.
United academy graduate Mainoo has been one of the club's players of the season after breaking into the first-team and going on to become a regular starter.
His performances earned him a call-up to Gareth Southgate's England squad and is now in-line for a place in the Three Lions squad at the upcoming European Championship.
Hojlund shook his head and pursed his lips as Mainoo's number flashed up on the fourth official's board
Hojlund and Mainoo later took their place on the bench alongside each other at Old Trafford
United manager Ten Hag explained his substitutions after the match and claimed younger players in his squad playing their first full senior season are susceptible to fatigue.
'I am the manager and have to decide what the team needs,' said Ten Hag.
'It was the right decision and totally logical to bring off very young players who are in their first year of the Premier League and feel some fatigue.
'They [Mainoo and Hohlund] have both had injuries this season and I want to protect them,' he added.