American CoCo Vandeweghe claims that after Yulia Putintseva beat her, 4-6, 6-1, 6-1, in the final round of qualifying in Brussels, the teenager and her father Anton approached her and insulted her.

“I have never played a person with worst sportsmanship... Putintseva,” Vandeweghe tweeted. "How can anyone comment on my game style after you have already won the match in such a negative way is unbelievable!

"Her exact words were ‘You are a terrible player, only serve. I win all the rallies.’ That comment is totally uncalled for...and on top of it your father clapping while you say this haha, unreal!" (See tweets in timeline here.)

Vandeweghe later told that there was no confrontation between the two during the match and that she said nothing to Putintseva, only things to the umpire.

Putintseva later tweeted: "And by the way saw a [tweet] of Coco... Wont comment much! Really surprise that people can act like that after losing to younger player. Think she is angry coz before the match she thought that im not her level of player.And by the way no matter who is at the other side i am respecting that person! And always shaking hand in the end of the match!"

Vandeweghe said a similar incident happened to her in juniors, but not as a pro. “I can handle the fist pumps and the 'Come On's' on double faults and let court winners, but saying anything while we are done playing is totally uncalled for. Just rude and immature is what I would call it. With the father on top of it.”

Jan-Michael Gambill, Vandeweghe's coach, also called out Putintseva: "It was a good tennis match but that girl's sportsmanship I question. Haven't ever seen someone fist pump double faults and let cords. For the entire match, and it detracts from the very good tennis."

Vandeweghe did get into the main draw as lucky loser.

The WTA is looking into whether Putintseva or her father can be fined for unsportsmanlike conduct.