Pogba's third-minute spot-kick settled the hosts' nerves as United allayed some of the doom and gloom predicted by Mourinho after failing to land a series of targets before Thursday's transfer deadline. "They're the ones with the power these days - unfortunately".
Former captain Michael Carrick and fellow coach Kieran McKenna informed Pogba that he would lead United in his first match since winning the World Cup.
Less than a month since Pogba scored in the World Cup final to help France lift the trophy, he was thrown straight into action by Mourinho despite just returning to pre-season training this week.
"It's not having just the armband", Pogba said of his view on leadership.
"We changed the goalkeepers with Lee because Joel [Pereira, loaned to Vitoria de Setubal] is such a good young goalkeeper that he needs to play".
"Having the armband it's not like, 'Oh, I will show that I am a real captain and have to do extra work, '" he said.
"For us, it will be a hard season because I had my plans, and I had my plans for many months, and I started the Premier League season without a situation I thought was possible".
"When we have everybody with you, everybody next to you know they want to fight for you, obviously it's going to be easier, you know?" he said.
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United gaffer Jose Mourinho claims he "needed six changes not three" in his side's season opener, with Anthony Martial seeing no game as other options had to take priority.
José Mourinho appeared to take aim at Ed Woodward, Manchester United's executive vice-chairman, for not sanctioning all of his transfer targets, with the manager saying maybe his title should be downgraded to "head coach".
Andreas Pereira. The talented young Belgian spent last season on loan at Valencia and got the surprise start in this one.
It's a tough call but it seems like Pogba will remain for now, even if his relationship with Mourinho is strained.
"We thought maximum 60 minutes but he managed (more than) 80".
Moments after leaving the stadium around 11.30 p.m., Pogba posted on social media: "I'll always give my best to the fans and my teammates no matter what's going on".
He added: "The thinking is he is a very good penalty taker and likes the responsibility of it and he is first choice".
"[Kasper] Schmeichel is very good on pens but no chance".