Scott McTominay admits captaining Manchester United for victory over FA Cup opponents Watford was "surreal".
United boss Ole Gunnar Solskjaer surprised the Scot by handing him the armband for the first time.
Solskjaer said: “I gave him the armband to test him, to see how he reacted.
“I wanted to see if there was any change in him and, luckily, there wasn't.
“He delivered, as he always does - Scott has everything a leader has to have.
“We have always trusted our young men coming through and Scott is one who we believe has the Manchester United DNA in him and knows what it is to be a Manchester United player."
After his fourth goal of the season, McTominay, 24, said: “When the manager told me it was a surreal moment.
"I've been here since I had just turned five, so that's 18 or 19 years associated with the club and it is a huge honour.
"I love this club and it has been my whole life."