Kristina Mladenovic upset third-round favourite Angelique Kerber at the 2019 US Open on hard court in the first round, winning 7–5, 0–6, 6–4. Kerber entered as the clear pre-match favourite at odds of 1.31, whilst Mladenovic was positioned as the underdog at 3.79. The German began competitively, taking the opening set to 5–7 before Mladenovic asserted dominance in the second, recording a decisive 6–0 shutout. The third set proved decisive, with Mladenovic edging through 6–4 to secure an impressive upset victory. The result represents a significant scalp for Mladenovic and raises questions about Kerber's form heading into the latter stages of the season.