World number five Stefanos Tsitsipas has been knocked out of the US Open after losing his men's singles first-round match against Colombian Daniel Elahi Galan. Tsitsipas lost with a scoreline of 0-6, 1-6, 6-3, 5-7 in 2 hours and 48 minutes. Meanwhile, world number one Daniil Medvedev has advanced to the second round after a straight-set win against Stefan Kozlov.