Caroline Wozniacki called the officiating a "disgrace" after being knocked out of the French Open in the third round Saturday, losing to Kaia Kanepi of Estonia 6-1, 6-7 (3) 6-3.
The former top-ranked Dane argued several line calls, including a ball that was judged to have hit the baseline early in the second set.
"It's a disgrace that mistakes like this are made," Wozniacki said. "It wasn't even like, 'Could have been in, could have been out.' It was clearly out."
The call came at 1-1 in the second set with Kanepi holding a break point. Wozniacki argued with chair umpire Poncho Ayala of Spain, who agreed with the original call that the ball hit the line.
"How can you sit there and be so arrogant?" Wozniacki said to Ayala. "Have you gone to school?"
After coming back to win the second set, Wozniacki again argued a line call in the third.
Kanepi, who finally won on her fifth match point despite being broken four times while serving for the match, said she wasn't affected by the uproar.
"Well, I think that those things happen in tennis matches, so it's OK if she wants to argue," Kanepi said. "I have to be ready for that and take it easy."
Wozniacki finished the last two years as the top-ranked player but has never won a Grand Slam title. Her best result at a major tournament was a runner-up finish at the 2009 U.S. Open.
The Dane has dropped to No. 9 in the rankings and has not won a title yet this year. She recently hired 2002 Australian Open champion Thomas Johansson as coach.