Caroline Wozniacki slammed chair umpire Renaud Lichtenstein as rude after arguing with him during her Australian Open third-round win over Kiki Bertens.
Wozniacki eased into the fourth round of the opening grand slam of the year with a 6-4 6-3 victory on Friday.
But she was infuriated by Lichtenstein as she served for the match as a line call went against her, allowing Bertens to save a first match point, the Dane then slamming her racquet in frustration as a second went begging.
A third was also spurned but Wozniacki, who also clashed with the umpire over supposed slippery conditions on court, eventually wrapped things up, setting up a meeting with Magdalena Rybarikova on Sunday.
Asked about Lichtenstein, Wozniacki told reporters: "I don't know. I've never had this guy before, I think. Maybe I just don't remember. But I think he did a poor job.
"If the court is wet, I think it's normal to ask for a towel. I don't think someone needs to be rude, and I told him so. I think there were some questionable calls, as well.
"Obviously on the first match point, it was out. He should have seen that, as well. I don't know. I think there's a way he can be strict but not rude, if that makes sense. I just think he was being rude.
"I told him so after the match, that the court was actually really slippery. It really shouldn't be that big of a problem just to clean it."
Wozniacki saved two match points in her second-round match with Jana Fett and, with a more routine win under her belt, the former world number one is putting that struggle behind her.
"It was definitely a little bit easier today than it was the other day," she added. "I'm going to take it and move forward and just call it a day."