Grégoire Barrere defeated Oscar Otte 6–4, 6–3 in the first round of the ATP 250 Stuttgart tournament on grass on 13 June 2023, upsetting the pre-match favourite. Otte entered as the odds-on favourite at 1.75 to Barrere's 2.19, yet the Frenchman controlled both sets with clinical serving and court positioning on the quick surface. Barrere's composed performance, particularly his ability to break Otte's serve and consolidate his own, proved decisive in securing the two-set victory. The result represents a significant scalp for Barrere on grass and suggests he may pose a threat in the subsequent rounds at Stuttgart.