 At the 2007 Pan American Games in Rio de Janeiro, Cielo won three gold medals in the 50-metre, 100-metre, and 4 × 100-metre freestyle events, and a silver medal in the 4 × 100-metre medley. In the 50-metre freestyle, he won the event with a time of 21.84 seconds, beating the Pan American Games record, and becoming the first swimmer from South America to swim it in under 22 seconds. Cielo began to get close to the world record in the 50-metre freestyle, a time of 21.64 seconds, which at the time belonged to legendary swimmer Alexander Popov. He also broke the Pan Am Games and South American record in the 4 × 100-metre freestyle, with a time of 3: 15.90, along with Fernando Silva, Eduardo Deboni and Nicolas Oliveira. It the 100-metre freestyle, he broke the Pan Am Games record with his time of 48.79 seconds, and in the 4 × 100-metre medley, he broke the South American record with a time of 3: 35.81, along with Thiago Pereira, Henrique Barbosa and Kaio Almeida.
