2023 BOSS Open – Singles
defeated Jan-Lennard Struff in the final, 4–6, 7–6, 7–6 to win the singles title at the 2023 Stuttgart Open. It was his third ATP Tour title, and his first on grass courts. Tiafoe saved a championship point en route to the title, in the final-set tiebreak. By winning the title, Tiafoe debuted in the top ten of the ATP rankings for the first time in his career.
Matteo Berrettini was the defending champion, but lost in the first round to Lorenzo Sonego.