Tennis: Mochizuki’s breakout run ends in Japan Open semifinals

World No. 215 Shintaro Mochizuki’s impressive run at the Japan Open tennis championships ended Saturday in a straight-sets semifinal defeat to 50th-ranked Russian Aslan Karatsev.

The 20-year-old Mochizuki, the 2019 Wimbledon junior singles champion, entered the ATP 500 event at Tokyo’s Ariake Colosseum as a wildcard without a win on tour but took down world No. 10 and top seed Taylor Fritz of the United States in the second round.

Mochizuki’s run in Tokyo included wins over 31st-ranked Tomas Martin Etcheverry of Argentina in the first round and 41st-ranked Alexei Popyrin of Australia in the qu...