NEW YORK—Daniil Medvedev reached the U.S. Open semifinals on Tuesday for the third straight year, ending the surprising run of qualifier Botic van de Zandschulp with a 6–3, 6–0, 4–6, 7–5 victory. The No. 2 seed from Russia dropped a set for the first time in the tournament but recovered to keep alive his bid for a first Grand Slam title. Medvedev got close in 2019, falling to Rafael Nadal in a fifth set, before losing to eventual champion Dominic Thiem in last year’s semifinals. “Just want to do a little bit better than last two times and get this last step, which is the toughest one actually,” Medvedev said. His match Tuesday couldn’t have started much easier. He broke six times in Van de Zandschulp’s first eight service games and won the second set in just 22 minutes. Van de Zandschulp, a 25-year-old from the Netherlands, was trying to …