Stanislas Wawrinka slammed his performance in the first round of the Japan Open on Tuesday, as he was beaten 7-5, 6-2 by Japanese wildcard Tatsuma Ito.
The top seed was beaten in 79 minutes on Center Court by the world number 103, in the first ever meeting between the two players.
It was the first ATP tour match the Swiss had played since losing to another Japanese player, Kei Nishikori, in the quarter-finals of the US Open earlier in September, with his only other match since then being a three set win over Italian Fabio Fognini in his country’s Davis Cup semi-final victory.
The world number four smashed his racquet on court at one stage, and he was disappointed with his showing in his last hard court tournament of the year.
The Australian Open champion told reporters: "It was certainly not a good day at the office. I'm not happy about the result.
"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."
Tough end to the season
Wawrinka will not have a sufficient amount of time to alter his tactical play, as he will be in action again at the Shanghai Masters next week, before playing in the final ATP Masters 1000 Series event in Paris at the end of October.
It will be a late end to the season for the world number three, as he is on course to qualify for the ATP World Tour Finals in London in November, before playing in the Davis Cup final against France later that month.
There were echoes in the 29-year-old’s comments of Spaniard David Ferrer’s views of his shock loss to compatriot Marcel Granollers on Monday, as he also vowed to take a look at his game in light of his defeat.
List of shocks
The tournament in Tokyo has had a number of surprises so far, as fifth seeded Frenchman Jo-Wilfried Tsonga was also beaten on Tuesday, as he was knocked out by Polish qualifier Michal Przysiezny in three sets.
Wawrinka, whose best result in Tokyo has been runs to the quarter-finals in 2009 and 2012, would have had aims of adding to his seven career singles titles.
Three of those titles have been won this year, with the first being his maiden Grand Slam title at the Australian Open in January, where he beat former champion Rafael Nadal in the final.
Despite his success in Melbourne, Wawrinka was not able to repeat that level of form in the other three Grand Slams, as he was knocked out in the first round of the French Open by the unseeded Guillermo Garcia-Lopez, and fellow Swiss Roger Federer beat him in the quarter-finals at Wimbledon before his loss to Nishikori in New York.