The birth of her first child led Serena to skip this year's Australian Open.  Getty Images

Tennys Sandgren created some controversy with his quarterfinal appearance at this year's Australian Open when it came to light that he had previously retweeted and conversed with some alt-right personalities, then subsequently scrubbed them when his Twitter account came under scrutiny. At least one star, however, isn't accepting his explanation that he just found it interesting. Serena Williams has called on Sandgren to apologize for the rhetoric.

Williams wasn't shy in expressing her feelings towards Sandgren on Tuesday night when Sandgren played his quarterfinal match, as she sent a tweet when he started.

On Wednesday, she addressed Sandgren directly, saying that she doesn't care for an apology. But she does know a lot of people that do.

Sandgren had previously tweeted an article about Williams yelling, adding his own comment: "disgusting..." ESPN's Chris Fowler went out of his way to explain that Sandgren shouldn't be type cast during the telecast of the quarterfinal match, but most people seem pretty set against Sandgren and his evasiveness about his political leanings.

Sandgren gave a very strange press conference after his elimination by Hyeon Chung, in which he said things like "you're hastening the hell you wish to avoid" and "You seek to put people in these little boxes so that you can order the world in your already assumed preconceived ideas." 

He also threw out the "just asking questions" defense, saying: "You would rather perpetuate propaganda machines instead of researching information from a host of angles and perspectives while being willing to learn, change, and grow." He's basically Kyrie Irving with a racket.

People aren't fond of Sandgren, and it takes a lot to turn Americans against you when you're the last man standing representing the U.S. One has to think it takes a lot to turn Serena Williams against you, too.