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.

Japan’s Shintaro Mochizuki plays a shot in his Japan Open semifinal against Russian Aslan Karatsev at Tokyo’s Ariake Colosseum on Oct. 21, 2023. (Kyodo)

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 quarterfinals.

It ended in a 6-3, 6-4 1-hour, 33-minute loss to Karatsev, against whom he managed just one break point.

In Sunday’s final, Karatsev will face 19th-ranked Ben Shelton, who defeated American compatriot Marcos Giron 6-7(2), 7-6(5), 6-4 in the first semifinal.

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