Tokyo - Tatsuma Ito has followed the winning example of compatriot Kei Nishikori as the number 103-ranked local dumped top seed Stan Wawrinka out 7-5, 6-2 in the first round of the Japan Open on Tuesday.
Another seed followed Wawrinka to the exits, as ailing French number five Jo-Wilfried Tsonga lost to Poland's Michel Przysiezny 4-6, 7-5, 7-6 (11-9) after nearly two and a half hours.
Tsonga, the 2009 champion, said he has been suffering for three days from a stomach virus and was lacking energy.
"I came here expecting to play good tennis. But it was not enough for me today, I didn't have enough energy to compete," he said.
"This virus has bothered me. I tried anyway to do my best on court, I gave everything but I was too tired."
Number three Milos Raonic, finalist at the last two editions, had no trouble as he fired 22 aces -- the last on match point -- to defeat Australian Bernard Tomic 7-6 (7/3), 6-3.
Ito showed no fear as he imposed his game on the Swiss world number four Wawrinka, who won the Australian Open in January.
"I played a very good match," said the winner. "It's the first time I have beaten a top five player. I tried my best every point and I was very focused. I was a little nervous, but I stuck to my game and I finished well."
US Open finalist and last week's Kuala Lumpur ATP winner Nishikori is seeded fourth at the home event he won in 2012 and opens his singles campaign Wednesday.
Wawrinka stands next in the queue to qualify as fourth man into the eight-player World Tour Finals in London in November.- Smashed racquet -
The Swiss was puzzling about what went wrong with his game in the 79-minute loss, which will make him wait until the Shanghai Open in a week's time before he is expected to enter the year-end field.
"It was certainly not a good day at the office. I'm not happy about the result," said Wawrinka, who smashed a racquet in his frustration on court. "I have to see what is wrong and try to change it before Shanghai.
"It was a bad match from my side. I felt slow on the court and was not moving well. It's tough to say exactly what went wrong.
"I've seen Ito play and knew his game. I allowed him to play aggressively and he had a good match. It's tough to say what happened to me but I have to work it out and make corrections before Shanghai."
Wawrinka said he was not worried about his London position -- only the state of his game two weeks after helping his nation into the Davis Cup final against France.
Fourth seed Nishikori will take his growing confidence into the concluding weeks, with hopes of becoming the first Asian man to qualify for the season final.
"I'm sixth now (in the season points race) and I'm really hoping to qualify," he said after a doubles win.
The Japanese player said it was the first year he had had the chance to reach the final.
"It's something that every player wants to play. I'm happy about standing sixth but I have a lot of work over the next weeks," he said.
"I'm pleased to be in this position but the race is very close and a lot of players are trying to earn a place. Some good results over the rest of this Asian swing will help, I'm hoping to do well."
The 24-year-old is Japan's only player in the ATP top 100, with the other six Japanese players still ranked within the top 170.
Nishikori won the Tokyo title in 2012 and is the only Japanese to lift the honour.
In first-round results, German Benjamin Becker beat Kuala Lumpur semi-finalist Jarkko Nieminen as the Finn retired trailing 7-5, 4-1. Two more players, Frenchman Edouardo Roger-Vasselin and sixth seed Roberto Bautista Agut, also failed to finish.
France's Gilles Simon saved six match points in the second set as he held on for the 4-6, 7-6 (9-7), 2-1 win when his opponent Agut could not go on.
Results from day two of the Japan Open on Tuesday (x denotes seeded player):
Benjamin Becker (GER) bt Jarkko Nieminen (FIN) 7-5, 4-1, retired
Donald Young (USA) bt Go Soeda (JPN) 6-4, 6-2
Tatsuma Ito (JPN) bt Stan Wawrinka (SUI x1) 7-5, 6-2
Gilles Simon (FRA) bt Roberto Bautista Agut (ESP x6) 4-6, 7-6 (9/7), 2-1 retired
Jurgen Melzer (AUT) bt Eduardo Roger-Vasselin (FRA) 7-5, 4-1, retired
Michel Przysiezny (POL) bt Jo-Wilfried Tsonga (FRA x5) 4-6, 7-5, 7-6 (11/9)
Jeremy Chardy (FRA) bt Rajeev Ram (USA) 7-5, 5-7, 6-4
Milos Raonic (CAN x3) bt Bernard Tomic (AUS) 7-6 (7/3), 6-3