​Manchester United manager Jose Mourinho has been tested on how well he really knows his players after being asked to see if he can identify his biggest Old Trafford stars from their childhood photos.

In a video clip from earlier this season that has resurfaced online, Mourinho was presented with an early photograph of the likes of Wayne Rooney, Zlatan Ibrahimovic, Paul Pogba and others, before offering his own little insight into his first impression of each.

What has impressed the United boss most about Rooney is his total lack of ego.

"He's a great kid - I still call him a kid - he doesn't behave like a star, doesn't behave like the top scorer in the England national team, doesn't behave as the captain, he's just a very nice kid."

West Bromwich Albion v Manchester United - Premier League

Mourinho's personal relationship with Zlatan Ibrahimovic extends back to 2008, and the veteran Swede is one whose public persona is apparently quite different from his private.

"My first impression of Zlatan was a long time ago when I went to Inter," Mourinho said.

"My impression was 'wow, he is much better than I thought'. And again, a guy that sell his image to the world, that is not him, he's another very nice guy."

Manchester United v West Ham United - Premier League

After struggling to immediately identify 'little' Pogba stood in a picture with older twin brothers Florentin and Mathias, Mourinho described the French superstar as "one of the happiest guys I've found in football".

While of David de Gea, he said, "I met him for the first time when I was at Real Madrid and he was coming through at Atletico. I thought immediately that skinny guy was fantastic."

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After having no problem getting Anthony Martial immediately, Mourinho described as the young forward as "a bit shy" and "very quiet" on first impression. But Martial is apparently quite the opposite once you get to know him.