The 19-year-old Spaniard sparked controversy with his reply to team-mate Jose Enrique, who had posted a bizarre picture of himself getting his teeth whitened.
Suso tweeted: ‘What f*** is he doing? This guy is gay… he does everything except play football.’
The Reds midfielder quickly realised he had made a poor error of judgement, deleted the tweet and made an apology.
But, after hearing of Suso’s punishment, Enrique tweeted: ‘Is amazing how fa can fine my friend @suso30fernandez for a banter thing. Was just a joke!!!’
An FA statement read: ‘Following an Independent Regulatory Commission hearing on Monday, Liverpool’s Jesus Fernandez Saez (Suso) has been fined £10,000 and warned as to his future conduct for a comment posted on Twitter.
‘The charge, which the player admitted and requested a paper hearing, was that he acted in a way which was improper and/or brought the game into disrepute in that the comment was posted on his Twitter account and included a reference to a person/s sexual orientation and/or disability.’
The teenager apologised on his Twitter page tonight, saying the ‘unfortunate’ comments were intended as a joke.
‘I’m very sorry if anyone has been offended by my comments about the photo of my team-mate Jose Enrique,’ he wrote.
‘It was only a joke between the two of us. I realise that my words were unfortunate and it was not my intention to offend anyone.
‘I apologise again if anyone was offended.’
Suso’s gaffe follows Jen Chang leaving his post as media chief following the Twitter storm with spoof blogger ‘Duncan Jenkins’.
Liverpool were forced to apologise to Jenkins, real name Sean Cummins, for the ‘inappropriate actions’ of Chang, after they met in a Manchester restaurant.
Chang wrongly believed inside information used by Cummins on Twitter had been fed to him by an Anfield mole.
The fan then alleged in a blog that Chang made a series of threats to him, which included revoking his shared season ticket.