Sebastian Bielen is ranked nr 1 in the USA among the 8th graders.
He is a member of Team USA and is sponsored by Lacoste (clothing) and Tecnifibre (equipment).
In 2022 Sebastian represented USA in the most prestigious tournament in the world - Les Petits As.
Sebastian won a Gold Ball in singles at the 2021 National Championships Easter Bowl and a Silver Ball in doubles at the 2022 Easter Bowl. He is mupltiply Level 2 and Level 3 National and Eastern sectional champion.
In 2022 Sebastian won the National Clay Court Championships in doubles and the National Hard Court Championships in singles, earning another two Gold Balls.
Together with the Team USA Sebastian won the 2022 America's Cup vs Teams from Canada and South America.
In 2023 Sebastian won the Bronze Ball at the 16's National Spring Championships Easter Bowl and made it to the top 1000 of the ITF ranking.
Sebastian won numerous National and International Little Mo tournaments:
In 2019 Sebastian got selected by the USTA to present the trophy to Rafael Nadal at the US Open final.