Japan’s Naomi Osaka won the match, becoming the country’s first Grand Slam singles champion.
The outburst had Twitter divided in the weeks that followed, with some people expressing disdain for “sexism” in the tennis world, and others calling Williams “spoilt”.
Though this flare-up is what many people remember about the tennis icon’s year, Williams had several other newsworthy moments.
When Prince Harry and Meghan Markle tied the knot in May, Williams and her husband Alexis Ohanian were among the high-profile guests.
Williams and Markle have been close since they first met in 2010.
Dressed in an asymmetrical pink dress and matching hat, Serena was an elegant figure alongside her husband, who wore a traditional morning suit.