Reilly Opelka defeated Novak Djoković 7–6, 6–3 in the Brisbane ATP 250 quarter-final on hard court on 3 January 2025, delivering a significant upset against the heavy pre-match favourite. Djoković entered as the overwhelming odds-on favourite at 1.06, while Opelka was priced at 12.64, yet the American produced a composed performance to claim victory in straight sets. The opening set went to a tie-break, which Opelka secured before consolidating his advantage in the second set with a decisive 6–3 scoreline. The result marks a notable scalp for Opelka and represents a rare early-tournament setback for Djoković, raising questions about the Serbian's form and fitness as the Australian Open approaches.