In the Herald Sun, Knight drew a cartoon that showed Williams having an on-court meltdown during the US Open final and the umpire urging her opponent, eventual victor Naomi Osaka, to let the 23-time grand slam victor win.
The Herald Sun reported on Tuesday that Knight had been mentioned on Twitter almost 74,000 times following the cartoon's publication.
"A champion tennis player had a mega tantrum on the world stage, and Mark's cartoon depicted that", editor Damon Johnston said.
"I'm not sure if my cartoon is superior to anyone else's, but people should know that my intent was to honestly caricature Serena Williams, and capture her athletic strength and also to depict her taking the racket of sexism and smashing it - a clearly labeled "male symbol" - with her righteous anger".More news: Assassin's Creed Odyssey Season Pass Includes Assassin's Creed III Remastered
Knight said that his phone "melted down" as criticism of his portrait roiled social media all day.
Other US media pointed out that Osaka was portrayed as petite and feminine with jet blonde straight hair - in real life she has dark curly hair with blonde streaks and is taller than Williams.
In early August, for a cartoon about train-station safety in the Australian state of Victoria, Knight also faced ire for how he drew faceless black figures fighting in the background.
The image triggered widespread allegations of racism against illustrator Mark Knight.
"I think it's disgusting".
As noted by the Herald Sun, fellow cartoonist Michael Leunig said Knight's cartoon was not offensive, but truthful.More news: Lloris gets driving ban for drink-driving
In 2016, Bill Leak was slammed for a cartoon that implied Indigenous fathers were alcoholics, poor parents and irresponsible, again painting a whole culture with historic and hurtful race-based stereotypes. The chair umpire gave Williams a game penalty-the punishment for a third code violation- for verbal abuse after she called him a "thief" and a "liar".
"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", Rowling wrote on Twitter.
"When I drew President Obama, I always focused on his eyebrows, his chin, his ears and his mole".
Knight's depicting "the world's greatest tennis player spit the dummy" appears in the foreground with the caption: "Vetoed: Large hair and lips, too angry".
Navratilova concluded in her piece: "I don't believe it's a good idea to apply a standard of 'If men can get away with it, women should be able to, too.' Rather, I think the question we have to ask ourselves is this: What is the right way to behave to honor our sport and to respect our opponents?"
"I thought they went over the top".More news: Russia, UN begin consultations on Syrian constitutional committee in Geneva