Shockwaves Through Sports: 15 Unbelievable Upsets That Redefined History!

Roberta Vinci Defeats Serena Williams, 2015 US Open

In the 2015 US Open, Italian tennis player Roberta Vinci, ranked 43rd, shocked the world by defeating Serena Williams, who was pursuing a calendar Grand Slam. Vinci's victory is one of tennis's biggest upsets, proving that any player can triumph on any given day.