At the 2014 FINA World Swimming Championships (25 m) in Doha, Qatar, Guido won a gold medal in the Men's 4 × 50 metre medley relay, formed by Guido, Felipe França Silva, Nicholas Santos and César Cielo, considered the "Dream Team" by Cielo (formed only by medalists or world champions in their respective individual events). Brazil won the gold shattering the world record with a time of 1:30.51. On December 7, Guido won his second gold in the Men's 4 × 100 metre medley relay, along with César Cielo, Marcos Macedo and Felipe França Silva, with a time of 3:21.14, South American record. Guido also finished 5th in the Men's 100 metre backstroke and 9th in the Men's 50 metre backstroke.