Cape Town - The Australian cartoonist who has come under fire for his depiction of Serena Williams insists he is not a racist.



Mark Knight's caricature, published in Melbourne's Herald Sun newspaper on Monday, shows a butch and fat-lipped Williams jumping up and down on her broken racquet at the US Open.



Williams' heated exchanges with an umpire at the tournament final this week have stirred the tennis world.



She was found guilty of code violations and fined US$17 000 - raising allegations that there are double standards for male and female players.



Knight was criticised in some quarters for being “racist and sexist”.



But he denies this in the video above.



Williams was thwarted in her bid for a record-tying 24th Slam singles crown in losing to Japan's Naomi Osaka.



In the cartoon the umpire is seen saying to Osaka "can't you just let her win?".