MANCHESTER, England -- Paul Pogba eschewed the opportunity to end talk that he is unsettled at Manchester United by insisting, "There are things that I cannot say, otherwise I will get fined."

The midfielder helped Jose Mourinho's team kick off their Premier League campaign with a 2-1 win over Leicester by scoring an early penalty in Friday's game at Old Trafford, coming at the end of a week during which there has been speculation about the Frenchman's future.

He has been linked with moves to Barcelona and Juventus after sources told ESPN FC the 25-year-old was unhappy at some of Mourinho's criticism of him during the summer. The United manager claimed during the tour of the U.S. that Pogba's form had improved during the World Cup because he was free from distractions and fully focused on football.

Speaking to reporters after the game against Leicester, Pogba was asked whether he is "happy and comfortable" at the club, but the £89.3 million man turned down the chance to put the speculation to bed.

"There are things, and there are things that I cannot say, otherwise I will get fined," he said.

Paul Pogba captained Manchester United against Leicester in his first competitive match since the World Cup final Getty

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."

Pogba endured a turbulent season at Old Trafford last term and was dropped for a crucial Champions League tie with Sevilla in favour of 21-year-old Scott McTominay.

Despite having just four days training after his post-World Cup break, he put in a match of the match performance against Leicester. And afterward the new world champion vowed to always work hard "for the people that trust me."

He said: "I always give my best for the fans, for the teammates and for the people that trust me.

"With the players that we have, of course we're Manchester United, we have to look at the top of the league. That's obvious.

"I mean, Manchester United, we have to show on the pitch, we have to play well, we have to be focused and we need people to trust us."

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Pogba returns to United having been lauded for his role in France's World Cup win. He scored in the final against Croatia and earned praise after the tournament when a video from inside the French dressing room revealed his inspiring team talk before facing Argentina in the round of 16.

"The players let me, I would say, lead and give me the space to speak, as well, and we have the same objective," he said about his successful summer with France, before pointedly picking out manager Didier Deschamps for special mention. "Everybody was on the same page. So, obviously it's easier for a player to be on the same page with all the group -- the manager was inside, the physio, the kitman, we were all a group in the team. So, obviously it's easier to go and speak and express yourself, and we went for an objective, and the big one was to win.

"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? It's going to be easier and it makes the team go higher.

"[United] is a different team, obviously. I still enjoying playing football, I still love football and I still give my best with the team, for the team. Like I said, when you are comfortable, when people trust with everyone or confident, are good in the head, it's going to be easier."

Pogba was named captain for night against Leicester, with Antonio Valencia sidelined with a calf injury.

It was well-timed after a week of stories about the strained relationship between player and manager, but the former Juventus man insists the armband didn't change anything once he got onto the pitch.

"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. "No, I just have to be myself and do what I know, do what I can do and do what I know to do. I always love the club. I love the club. I came in the academy, I grew up. I came from the academy, I played for the first team. For me, it was a dream come true. And wearing this, it's even more because of the past, because of the players that played here, the people that have been wearing this. It's obviously an honour for me.

"Like I said, when I have this, I have the confidence of the fans. They're all here, they help me, my teammates, obviously it makes me want to give them love and give them good performances on the pitch."