Serena Williams' rant against an umpire in the US Open Women's Final on Saturday has divided viewers, with many Twitter users calling her 'disgraceful' but fans insisting she was only standing up for herself.

Williams accused Carlos Ramos of being a 'thief' as she lambasted him for giving her opponent Naomi Osaka a point after she received instruction from her coach. The outburst led to a whole game being handed to Osaka, who went on to win 6-2, 6-4.

Mark Zeigler tweeted: 'Serena Williams kept telling the chair umpire: 'You owe me an apology. Say you're sorry.' How about Serena apologizing to Naomi Osaka, who grew up idolizing her, for ruining her moment?'

Serena Williams ranted at US Women's Final umpire Carlos Ramos for her extraordinary on-court rant on Saturday

The 23-times grand slam champion was lambasted as a 'shame to the sport' on Twitter

Other viewers called her behavior 'disgraceful' and said her coach had admitted to the violation.

Basket Tennis wrote: 'Tennis did not deserve this shame. Ramos did not deserve that. The tournament did not deserve that. @Naomi_Osaka_ did not deserve that. She couldn't even celebrate the biggest achievement of her entire life. @serenawilliams is a shame for the sport.'

Dave Williams said: 'That was coaching...she should have moved on and kept her cool knowing that the penalties would only get worse.'

Jimmy tweeted: 'Serena Williams what a lowlife. Disrespecting the umpire with her verbal abuse and breaking her racket. Disgraceful.'

Another user said: 'I hope Serena Williams apologizes to the whole tennis world. Her coach has already admitted he was actually coaching.'

But supporters of Williams flocked to her defence, saying she was only standing up for herself.

'I can't think of another pro sport in which officials treat arguably the greatest player ever like @serenawilliams was treated today,' wrote Jamil Smith.

Another fan wrote: 'So let me get this straight: @serenawilliams shows her emotions during a game and sticks up for herself, and she is described as 'having a tantrum.'

'But male athletes do the same - across many sports - and they are described as 'being competitive.' #usopen.'

William's coach Patrick Mouratoglou also came to her defense, tweeting sarcastically after the game: 'The star of the show has once against been the chair umpire.'

US tennis star Andy Roddick also criticized the umpire's actions.

Many Twitter users criticized Williams (left) for overshadowing the triumph of her opponent Naomi Osaka (right)

But supporters of Williams flocked to her defence, saying she was only standing up for herself

Shortly after the match, Williams' coach, Mouratoglou tweeted: 'The star of the show has been once again the chair umpire'

Mouratoglou followed that tweet up with: 'Congratulations for Naomi Osaka for a fantastic tournament'

Trying to regain some dignity and composure during the presentation ceremony, Williams appealed for calm: 'I don't want to be rude. She played well. Let's make this the best moment we can, let's not boo any more.'

The trouble started when her coach was called for giving hand signals illegally in the first set, and then spiralled when she slammed her racket into the ground when broken back for 3-2 in the second, after which she was given a point penalty.

She repeatedly insulted the umpire, calling him a liar and a thief and demanding an apology. He duly docked her a game after the third code violation, leaving her at 3-5, from which she could not recover.

It detracted from a magnificent performance from the American-raised Japanese player, and made for an embarrassing trophy handover, at which Williams was described as a 'role model'. Not in this particular case she wasn't.'

The whole incident was reminiscent of Williams's loss of control on the same arena when she threatened to ram a ball down a line judge's throat in 2009.