Naomi Osaka said she is still coming to terms with her US Open victory a day after defeating Serena Williams in a controversial final."It still doesn't really feel that real," said Osaka."I think right now what I'm feeling is very tired. So hopefully as that wears off then I'll start feeling more happy."On Saturday, the 20-year-old became Japan's first Grand Slam singles champion after defeating Serena Williams 6-2, 6-4 in a match that will most certainly go down as one of the most controversial major finals in history.Williams faced both a point penalty and game penalty during the match after a number of violations, including coaching, racquet abuse & verbal abuse towards the umpire.During Saturday's dramatic events, Williams was seen shouting at the chair umpire, demanding an 'apology' and claiming that Carlos Ramos was a 'theif' and a 'liar', which the American was later fined $17,000 (£13,100) for.

The controversy continues

If the events of Saturday wasn't enough for tennis fans around the world to be upset about, there's been more controversy added to the aftermath of the weekend's final.

That's because following Williams' claims that the penalties she received were 'sexist' and 'unfair', retired British tennis player Andrew Castle has made comments on social media that appear to have angered many fans.

Castle took to Twitter to voice his thoughts on the events from the weekend, but it's they way he's said it that has got so many people seeing red.

"I am playing tennis tomorrow. If I get a bad call I am going to smash my racket, protest that I am a father (so!), call my opponent a thief, demand an apology and claim that I have been treated differently because of my gender." Castle posted on Twitter.

"Than I will go home and grow up."

One can only assume this was the three time men's doubles ATP title winner's way of saying that Serena Williams' behaviour was childish and that perhaps she needs to 'grow up'.

Whatever Castle was trying to suggest, it certainly angered and upset many fans around the world.

You can see some of the reaction below.

One thing we know for certain is that gender equality in sport is still an issue that many people are concerned about. But does this point excuse Williams for her behaviour or has Castle crossed a line?