Manchester United fans loved the clip of Jose Mourinho refusing to sign a Chelsea shirt last year.

The Portuguese had recently been appointed Louis van Gaal’s replacement at Old Trafford when, on Man United’s pre-season tour of China, a Chelsea shirt was held out in front of him.

But, shaking his head, Mourinho turned down the request, continuing to sign Man United shirts only.

The video went viral on the internet but more attention would have been paid to it had Mourinho signed the Chelsea shirt.

Man United fans would have wondered what on earth their manager was doing. Chelsea fans would have laughed their heads off.

So, as much as the Chelsea supporter would have been disappointed by Mourinho’s refusal, the 54-year-old saved himself a lot of grief and unnecessary backlash.

Watch: Mourinho refuses to sign Chelsea shirt

Nainggolan was in a similar position

AS Roma midfielder Radja Nainggolan found himself in a similar situation recently when he was asked to sign a Juventus shirt.

Roma recently played the Serie A winners in the International Champions Cup in Foxborough, Massachusetts, with Juventus emerging victorious on penalties after the match finished 1-1.

Nainggolan had just finished a training session with his teammates when he stopped to take photos and sign autographs for fans.

Every Roma supporter got their photograph taken with the Belgian, or got his autograph.

But one sorry Juventus fan didn’t.

A Juve fan approached Nainggolan and asked him to sign his shirt. But the 29-year-old refused, asking the fan: “How could I sign that?”

The supporter pleads with Nainggolan but he doesn’t budge, instead continuing to meet Roma fans.

Watch the video below.

Watch: Nainggolan meets a Juventus fan

It’s hard not to feel sorry for the Juventus fan. He really wanted Nainggolan’s autograph.

The 29-year-old, who has been linked with a move to the Premier League, recently signed a new four-year contract with Roma.

"I think I have demonstrated that this is what I always wanted," the Belgium international said, per BBC Sport.

"I'm very happy that the club and I can continue our adventure and move forward together."

Nainggolan’s decision to stay at the Stadio Olimpico, when Mohamed Salah, Antonio Rudiger and Leandro Paredes have all left this summer, pleased Roma midfielder Kevin Strootman.

“I am happy that Nainggolan and Daniele De Rossi stayed at Roma,” Strootman told Sky Sport Italia, per the Daily Mail.

“Daniele is our captain, while every club in Europe wanted Radja, but he stayed here and we are happy about that. Roma did a great job by keeping them and we're stronger for it.”

Should Nainggolan have signed the Juventus shirt? Let us know in the comments section below!