TOKYO — Japanese wild card Tatsuma Ito upset Australian Open champion Stan Wawrinka 7-5, 6-2 in the first round of the Japan Open on Tuesday.
The No. 103-ranked Ito converted all four of his break-point chances to dispatch top-seeded Wawrinka at Ariake Coliseum.
He moved on to meet Benjamin Becker of Germany, who was leading Jarkko Nieminen 7-5, 4-1 when the Finn retired due to fatigue.
"It is the first time I have beaten a top-five player," Ito said. "I tried my best on every point, and I was very focused. I was a little nervous, but I stuck to my game, and I finished well."
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.
"It was not a good day at the office," Wawrinka said. "He started well, and then I was trying to come back in the match. First-round matches are never easy."
In another upset, Michal Przysiezny of Poland rallied from a set down to defeat fifth-seeded Jo-Wilfried Tsonga 4-6, 7-5, 7-6 (9).
Also, Jeremy Chardy of France and Donald Young of the United States were winners.