Tokyo – Japanese wildcard entry Tatsuma Ito upset Australian Open champion Stan Wawrinka 7-5, 6-2 on Tuesday to advance to the second round of the Japan Open.
The No. 103-ranked Ito converted all four of his breakpoint chances to dispatch top-seeded Wawrinka in 1 hour, 19 minutes at Ariake Coliseum.
He will now play Benjamin Becker of Germany, who was leading Jarkko Nieminen 7-5, 4-1 when the Finn retired due to fatigue.
The early exit could dent Wawrinka's chances of qualifying for the ATP finals in London in November. The top eight players qualify.
Wawrinka, who won his Grand Slam breakthrough title at the Australian Open in January, is ranked No. 4 and could have ensured a spot at the ATP finals by reaching the final in Tokyo. – Sapa-AP