古斯塔沃•坪井

In World Championships, Tsuboi's best campaigns in singles were the 2nd round in 2011, 2013, 2015 and 2021. His best performance was in 2013, when he managed to make it difficult for the Chinese player Zhang Jike, almost winning the first set and winning the second. In doubles, Tsuboi reached the 3rd round (round of 16) three times, in 2009, 2015 and 2017, each time losing by 4 sets to 2. The best campaign was in 2009, when playing in Japan and making it difficult for the Japanese duo to win, who ended up being bronze medalists in the tournament. In mixed doubles, Tsuboi managed to reach the 3rd round (round of 16) in 2013, being eliminated by the Chinese pair seeded n.2, but managing to win a set of them.

At the Table Tennis World Cup, Tsuboi made history by reaching the quarterfinals of the competition in 2015, equaling Brazil's best result in the tournament's history. Until then, Cláudio Kano, in 1987 and 1989, had also reached the quarterfinals. He also reached the round of 16 in 2017 and 2018.

At the 2018 World Team Table Tennis Championships, Tsuboi reached the quarterfinals playing with Hugo Calderano and Eric Jouti.

2021

At the WTT Star Contender in Doha, held in March 2021, Tsuboi reached the round of 16 after defeating the Japanese Koki Niwa (17th). He was eliminated by South Korean Jeoung Youngsik, 13th in the world rankings.

2020 Olympic Games

At the 2020 Olympic Games in Tokyo, Tsuboi, 37th in the world, by defeating Nigerian Quadri Aruna (21st in the world ranking), became the 3rd Brazilian in history to reach the round of 16 in the Olympics. The feat had only been achieved by Hugo Hoyama (Atlanta-1996) and Hugo Calderano (Rio 2016).