Ōi is one of Japan’s most accomplished pool players, recently reaching the final of the 2025 European Open Pool Championship. He has consistently delivered strong performances on the global stage, including a semi-final finish at the 2012 World Pool Championship, a fifth-place showing at the All Japan Open, and six appearances representing Japan at the World Cup of Pool.

In 2024, Ōi captured his first World Nineball Tour ranking title at the Taom Maxrack Nineball Helsinki Open. In 2023, he placed 4th at the Premier League Pool, 5th at the International Open, and previously secured 9th place finishes at the 2021 and 2022 World Pool Championships, as well as a 3rd-place finish at the 2021 US Open Pool Championship.