20 Biggest Upsets of 2018

8. Serena Williams Loses to Osaka

Serena Williams is the greatest female tennis player of all-time and one of the greatest athletes to ever live. So, whenever she loses a match it is an upset.

This year, Williams returned to the court after having her baby and made it to the U.S. Open Finals were, she squared off against Naomi Osaka.

It was a controversial match, in which Williams got into a dispute with a line judge, the 20-year-old Osaka defeated her childhood hero to become the reigning U.S. Open champion.