Jose Mourinho's son has labelled Chelsea fans a 'disgrace' and the 'worst [he's] ever seen' after they booed Cesc Fabregas during Sunday's 1-1 draw with Southampton.

Jose Mario, 15, a goalkeeper at Fulham, defended the Spanish midfielder and insisted he did not deserve to be singled out for criticism.

Fabregas has struggled to hit the heights he set during the first half of the season when he made 13 assists and Jose Mario claimed supporters were on his back on Sunday.

Jose Mario Mourinho (left, watching a game last season and with his dad) has criticised Chelsea fans

Jose Mario celebrates winning Chelsea's Capital One Cup victory with some of the players

Jose Mario took to Instagram to criticise Chelsea's fans before deleting his account

Jose Mario stands up behind the Chelsea dugout as he watches the team play Manchester City in 2013

Cesc Fabregas was booed by some Chelsea fans during Sunday's draw with Southampton at Stamford Bridge

The 27-year-old has not scored or assisted a goal in his last 10 games in all competitions and the last goal he made was against Swansea on January 17.

But Jose Mario, who is regularly seen at Stamford Bridge supporting the team and celebrated on the Wembley pitch with players after Chelsea won the Capital One Cup earlier this month, wrote on Instagram: 'Why is everyone hating and blaming Fabregas for Sunday's performance… It was a team effort.

'Fabregas might have not played as well as most expected but at least he kept fighting… Showed a lot of character, I've seen bad Chelsea fans but Sunday was the worse I've ever seen, Fans booing Cesc not singing at all, I completely agree with the chant 'Mourinho's right, you're fans are s****'

'Our fans are a disgrace!!!!'

Fabregas (right) has come in for criticism from supporters in recent weeks after a dip in form

Jose Mario tells one Instagram user that the clubs young players are not ready to play in the Premier League

Mourinho with his wife Matilde Faria

Responding to comments left by other Instagram users, Jose Maria also wrote that:

He would show Chelsea fans respect when they respect the team

That club staff hate Chelsea fans because of their criticism of the team

Fans were wrong to criticise Willian, Oscar, and Branislav Ivanovic

Chelsea's young players are not good enough to play in the Premier League yet

That fans should listen to his opinions because he knows more than them

Responding to two users criticism, Jose Maria wrote: 'I'll show the fans some respect, when the fans respect the team.'

To another user, he wrote: 'Who has been scoring goals??? Iva... Willian he is just having a bad time, every player has that doesn't mean you can boo them and put their momentum down... Oscar, he hasn't done anything wrong, please elaborate, cuz I don't see anything wrong with him.'

To the same user, he also wrote: 'That's why every single staff of Chelsea hate Chelsea fans!! Oscar has created a lot of our chances... Willian and Ivanovic are probably the players who track back the most they don't stop running Ivanovic has saved us this season, scored so many goals and helped beat Liverpool with their s****y youngsters... Willian put the cross in... You need to remember who you are talk to and realise I know a lot more than you.'

And in a third exchange with the same user, he added: 'Does it look like any of our youth are good enough to play in the best league in the world... No they are too young too weak... if fans kept supporting Fabregas he could change his mind set, booing him won't make him better at all.'

Jose Maria has since deleted his Instagram account. Chelsea refused to comment when approached by Sportsmail on two occasions.

Jose Maria is following in his dad's footsteps in criticising Chelsea's fans. At the end of last year, Mourinho was unhappy at the support his side were receiving at Stamford Bridge.

Speaking in November, Mourinho said: 'I can clearly say we are the team to get less support in home matches. I think it’s getting worse. When comparing to my pre­vious time, I think it’s getting worse. I don’t question the passion and the love – I’m nobody to question that and I know clearly that’s not true.

'Chelsea fans show us their passion for this club every day, but there is a certain line of living [way of behaving] at the matches at Stamford Bridge.'

Jose Mario also claims all Chelsea staff hate Chelsea fans and tells him to listen to his views

Jose Mario claims he will respect the Chelsea fans when they respect the team