Thiago Machado Vilela Pereira is a retired Brazilian international competition swimmer. One of the greatest swimmers in the history of Brazil, Pereira won the silver medal in the 400-meter individual medley at the 2012 Summer Olympics in London, beating the then-current Olympic champion Michael Phelps. He also broke a world record in the short course 200-meter individual medley, and broke several South American and Brazilian records. During his career, he competed with swimming legends Michael Phelps and Ryan Lochte.

Michael Fred Phelps II is an American former competitive swimmer. He is the most successful and most decorated Olympian of all time with a total of 28 medals. Phelps also holds the all-time records for Olympic gold medals (23), Olympic gold medals in individual events (13), and Olympic medals in individual events (16). At the 2004 Summer Olympics in Athens, Phelps tied the record of eight medals of any color at a single Games, held by gymnast Alexander Dityatin, by winning six gold and two bronze medals. Four years later, when he won eight gold medals at the 2008 Beijing Games, he broke fellow American swimmer Mark Spitz's 1972 record of seven first-place finishes at any single Olympic Games. At the 2012 Summer Olympics in London, Phelps won four gold and two silver medals, and at the 2016 Summer Olympics in Rio de Janeiro, he won five gold medals and one silver. This made him the most successful athlete of the Games for the fourth Olympics in a row.