Anastasia Rodionova became only the second player on the WTA Tour to be disqualified from a match when she hit a ball at supporters in the stands.
Rodionova tries to explain where she hit the ball after losing a point
Germany's Angelique Kerber was handed a 4-6 6-4 1-0 victory at the Cincinnati Open after the Russian smacked the ball at fans cheering for her opponent.
Without warning, Rodionova was defaulted by tournament referee William Coffey for unsportsmanlike conduct.
She said: "I've never seen in my life anyone defaulted in this situation."
In the 36-year history of the tour, the only one other default in the main draw of a tournament was Irina Spirlea who was disqualified in 1996 at Palermo for directing abusive language at an official.
Rodionova added: "I'm shocked. I still don't understand why they defaulted me. I'm really upset.
"I had no warning. I didn't hit the ball at anybody. I didn't swear at anybody. I didn't throw my racquet."