>> Team USA already making an Olympic-sized splash in Rio. Swimmer Katie Ledecky breaking her own world record Sunday to win the women's 400 meters freestyle gold. Britain's Adam Peaty following suit, shattering his world record in the 100 meters breaststroke, the first British male swimmer in nearly 30 years to grab Olympic gold.
Also crushing it, first-timer Simone Biles, the US gymnastics team blowing away the competition and qualifying by almost ten points, propelled by Biles' gravity-defying performance. Russian competitors now calling the Americans unbeatable. But Sunday was the end of the line for a tried and tested Olympic duo. Serena and Venus Williams crashing out of doubles in the first round, falling to Czech pair Barbora Strycova and Lucie Safarova and ending any hopes of a third successive doubles crown.
But the biggest upset in tennis, the world's top player, Novak Djokovic, dumped out of Rio in the first round by Argentina's Juan Martin del Potro, currently ranked 145th worldwide. On the diving board, China's Wu Minxia made Olympic history, becoming the game's most decorated female diver after winning gold in the women's three meter synchronized springboard.
The Chinese team is gunning to sweep all of the eight top spots in diving after grabbing six at the last Olympic Games in London.