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 also 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 loss to Karatsev, against whom he managed just one break point in a match that lasted a little over 90 minutes.
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.