Melbourne - Controversial American tennis player Tennys Sandgren has emphatically denied holding far-wing political views, while thanking his critics for keeping him "intellectually honest".
The 26-year-old, a devout Christian, came under intense scrutiny at the Australian Open last week over his apparent support on Twitter for alt-right groups in the United States.
He was also accused of homophobia, with Serena Williams saying an "entire group of people deserves an apology" over a tweet he posted in 2012 about a visit to a gay club that he said left "his eyes bleeding".
In a long statement on Twitter late Saturday, Sandgren, who was largely obscure before his Grand Slam exploits, said he had been naive and did not understand how "hurtful and confusing" his actions were.
He said he had only been attempting to learn from both sides of the political divide.
"I followed and interacted with a wide variety of people from different backgrounds and ideologies from the right and left of the political spectrum," he said.
"Regrettably, a few of those people were from the alt-right community. What I thought was something harmless and innocuous, I see now as being understandably hurtful and confusing. I am sorry for that.
"So, let me emphatically say that I do not hold any alt-right views, and I denounce any implied association with that group."
Among his now wiped tweets was one where he appeared to back a debunked online conspiracy in 2016 which linked Hillary Clinton to a supposed child sex abuse ring at a Washington pizzeria.
He also retweeted a video from white nationalist Nicholas Fuentes.
After being thrust into the spotlight in Melbourne during his run to the quarter-finals, Sandgren lashed out at the "dehumanising" media in a sermon-like statement at a post-match press conference after his Twitter postings came to light.
But he has seemingly now changed his tune.
"I would like to thank my critics and detractors for their help in keeping me intellectually honest to the image of the man I want to be," he said in his latest statement.
"I would like to thank the diverse legends of the tennis community who for their patience and understanding, and most importantly for their example in what it truly means to fight and never give up."