Daniil Medvedev defeated Hugo Dellien 6–3, 7–5, 5–7, 6–3 in the first round of the 2019 US Open on hard court, a result that confirmed pre-match odds heavily favouring the Russian, who entered as a strong favourite at 1.03. Dellien, the Bolivian underdog at 19.16, mounted brief resistance in the third set but could not sustain the challenge as Medvedev reasserted control to close out victory in four sets. The win marked a solid opening for Medvedev at Flushing Meadows as he advanced to the second round.