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 semifinal 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.

The Dutch qualifier had enjoyed a remarkable run, taking down 11th seed Diego Schwartzman to reach his first Grand Slam quarter-final, where he fired off 20 forehand winners and was the first player here to take Medvedev past the two-hour mark.

But the 2019 runner-up, who had 13 aces in the match, came roaring back in the fourth set, winning all but two of his first-serve points and never facing a break point.

Van de Zandschulp fended off match point in the 10th game, holding his serve to wild applause from a rowdy New York crowd, but Medvedev responded with a quick hold and a break, helped by a double fault from the Dutchman.

Medvedev, who lost in the semifinals a year ago to eventual winner Dominic Thiem, is one of the main candidates aiming to thwart world number one Novak Djokovic’s bid for a calendar Grand Slam.

“(I) just want to do a little better than the last two times and get this last step, which is the toughest one, actually,” he said.