NEW YORK: Russian fifth seed Daniil Medvedev advanced to his first Grand Slam quarter-final Sunday at the US Open by defeating German qualifier Dominik Koepfer 3-6, 6-3, 6-2, 7-6 (7/2).
Medvedev, coming off a US Open tuneup title last month in Cincinnati will face either Swiss 23rd seed Stan Wawrinka, a three-time Grand Slam champion, or top-ranked defending champion Novak Djokovic on Tuesday for a semi-final berth.