The Scotland international scored the only goal of the game to fire the Red Devils into round four
With Harry Maguire handed a rest – albeit he came on due to an injury to Eric Bailly – McTominay was handed the captain’s armband by manager Ole Gunnar Solskjaer for the first time in his United career.
Following the match, McTominay gave his feelings on what it felt like to lead out the club he has been with for more than 18 years.
“When the manager told me it was a surreal moment,” McTominay told BT Sport. “I have been at this club since I’d just turned five years old, so 18 years associated with this football club.
“So to get that is a huge honour. I love this football club and it has been my whole life, so it is a real honour.
“The manager has been nothing but amazing for me since he came to the club.
“I have a lot to thank him for and the best way to thank him is to put in performances on the pitch and doing the best I can.
“As long as I have got the manager’s trust I am happy and will keep doing my job every day in training and matches as well.”
United started brightly and took the lead on five minutes when McTominay headed home, but a much-changed side did not put the match to bed.
McTominay felt the changes contributed to some patchy play, but believes it will benefit the club down the line to get minutes into fringe players’ legs.
“We started really well,” he said. “For the first half an hour we were really good, we moved the ball well, the combination play was really good. But we just did not find it after that.
“For the boys who came into the team it is difficult as they have not played for a long time and it is about finding your rhythm.
“First 30 minutes I bet [Solskjaer] wasn’t expecting the rhythm we got, but then maybe a combination of tired legs and tired minds.”