Tokyo - Brazil tennis player Guilherme Clezar apologised on Saturday for making what appeared to be a slit-eyed gesture during his country's Davis Cup tie with Japan.
While denying any racist intent, the 24-year-old could be in hot water following an incident during Friday's defeat by Yuichi Sugita in a world group playoff in Osaka.
After successfully challenging a line call, an exasperated Clezar stretched his eyes in an apparent criticism of the line judge.
The gesture was caught on local television, but the player insisted he had not meant to insult Japanese people in a post on the Brazilian tennis federation's Facebook page.
"I want to underline that I never had the slightest intention to be aggressive, racist, prejudiced or anything of the type against Asian people," said Clezar, who lost the opening rubber 6-2, 7-5, 7-6 before Brazil fell 2-0 down in the tie.
"We have been extremely well received here and I have an excellent relationship with all tennis players from many different countries on the circuit," he added.
"Even though I didn't mean any prejudice, I recognise the gesture doesn't ring true with the attitudes of respect, enthusiasm, solidarity, emotion and many other things that sport means to us and I want to express my regret and my most sincere apologies."
The International Tennis Federation declined to comment, although local media reported that the ITF were investigating the incident.
Brazilian media reported that the ITF and Brazilian officials were scheduled to meet on Saturday.
Clezar, who also issued an apology from his Instagram account, is ranked 244th in the world and mainly competes on the Challenger tour.
Japan took a stranglehold on the Osaka tie after Go Soeda followed Sugita's win over Clezar by squeezing past Thiago Monteiro with a nervy 3-6, 6-4, 6-3, 6-7, 6-4 victory.
With Japan on the brink of returning to the Davis Cup world group, however, typhoon rain washed out Saturday's doubles rubber.
Japanese pair Yasutaka Uchiyama and Kiwi-born Ben McLachlan are now set to face Marcelo Melo and Bruno Soares on Sunday, weather permitting.
English Premier League football club Chelsea were forced to issue an apology in July after social media posts by Brazilian winger Kenedy that insulted Chinese people during a preseason tour to the Far East.