Serena'a US Open final meltdown: Who's saying what on Twitter after Naomi Osaka defeated the American in a stormy final on Saturday:

"Thank you @serenawilliams total class at the speech and you truly are the goat." -- Osaka's coach Sascha Bajin, a former hitting partner of Williams, on Twitter.

"If it was men's match, this wouldn't happen like this. It just wouldn't." -- Two-time major winner and former world number one Victoria Azarenka on Twitter.

"The star of the show has been once again the chair umpire. Second time in this US Open and third time for Serena in a US Open Final. Should they be allowed have an influence on the result of a match ? When do we decide that this should never happen again ?" -- Serena's coach Patrick Mouratoglou on Twitter.

"@espn just showed Serena and coach while he was "coaching". She wasn't even looking. Believe what you want." -- Former US men's player Mardy Fish.

"Congratulations on winning the 2018 @usopen, @Naomi_Osaka_. This win is just the beginning of a bright future. Tennis is in an exciting place right now with players like you. #Champion #usopen" -- Billie Jean King.

"Serena is a champion & doesn't deserve it -- the same way that Naomi is a champion & doesn't deserve this atmosphere for her first GS title!" -- French WTA player Kristina Mladenovic.

"I also agree with what Patrick said that pretty much all players receive coaching on court. The first warning for me is the most questionable one. Also hard that coaching at WTAs and qualies of slams is okay but not MD slams." -- British player Liam Broady on Twitter.

"It's all on the umpire of course. I was sad to see that Naomi was crying like she lost this final, but she was just playing better today.And no doubt Serena is the greatest champion and GOAT, but that's rules. It was really heartbreaking final." -- Russian tour player Elena Vesnina.

"Mother of all meltdowns" -- New York Post headline.