Barthel laced what appeared to be a cross-court backhand winner against Caroline Wozniacki when an onlooker in the stands shouted, "Out!" Soon realizing there wasn't a true "out" call, Wozniacki approached the chair to argue, when the fact was she had no play on the ball. The game was to continue rightly when the umpire said it was Barthel's point, and back to deuce. (Wozniacki led at this time, 7-6, 3-1. She would go on to win the match.)
The overwhelming problem here is that papa Piotr opted to get involved, to throw his paternal "weight" in on the matter—and from the stands. He yelled comments to the chair, and umpire Julie Kjendle actually acknowledged him and replied. See it here:
What's worse is that an official, potentially a security officer or someone higher up in the ranks, then approached Piotr, and it has been reported that he was asked to leave and, obviously, refused to do so. Later in the tournament, this tizzy occurred on the same chair umpire's watch:
It was not a great week to be Julie Kjendle.
[Thanks to @The_Changeover for the videos.]
—Jonathan Scott (@jonscott9)