NEW YORK (Reuters) - World number two Daniil Medvedev dropped his first set at this year's U.S. Open but eventually overcame Dutchman Botic van de Zandschulp 6-3 6-0 4-6 7-5 to reach his third straight semi-final at Flushing Meadows on Tuesday.

Van de Zandschulp outlasted the Russian in a 20-shot rally and then converted on break point in the fifth game before taking the third set on Arthur Ashe Stadium, the first sign of weakness Medvedev has shown since arriving in New York.