Serena Williams' loss to Naomi Osaka in the US Open final on Saturday is still causing consternation and controversy across the tennis world.

The latest bit of fuel to the fire: A cartoon depicting a tantrum-throwing Williams that appeared Monday in the Melbourne, Australia, newspaper The Herald Sun. Social media erupted with charges of racism.

Among the outraged: Harry Potter author J.K. Rowling, a noted Serena fan.

"Well done on reducing one of the greatest sportswomen alive to racist and sexist tropes and turning a second great sportswoman into a faceless prop," she tweeted.

Her response drew more than 10,000 retweets and 47,000 likes ... and counting.

Williams was fined $17,000 for three violations in Saturday's final. Debates have raged about whether chair umpire Carlos Ramos unfairly penalized Williams.

Was Ramos simply following the rules? Would he have punished a man the same way, or was sexism part of the story?

The particulars: Already down a set after losing 6-2 in the first to Osaka, the 23-time Grand Slam champion was in tears during an argument with Ramos after being given two warnings, one for coaching and one for smashing her racket, after Osaka broke her serve.

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Williams went on to call Ramos a thief and demanded an apology from the 47-year-old umpire.

After the match, the Flushing Meadows crowd booed Ramos, who was escorted off the court. Chair umpires are usually given a gift during the trophy ceremony, but that wasn't the case on Saturday.