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Botic van de Zandschulp's breakthrough Grand Slam performance came at the US Open in 2021. The Dutch tennis player reached the quarterfinals of the tournament, becoming the first Dutch man to reach the quarterfinals of a Grand Slam since Martin Verkerk in 2003. Van de Zandschulp's impressive run included victories over 11th seed Diego Schwartzman and 23rd seed Jannik Sinner.