06/30/2009 at 10:00 AM EDT
Anna Kournikova ended up with cuts on her neck after getting into a shoving match this past weekend in Las Vegas
The former tennis ace got into a scuffle inside Lavo Nightclub on Saturday night at the HardBat Classic party after another woman at the club threw a drink on her, PEOPLE has learned.
An onlooker said Kournikova, 28, and her assistant were sitting at a VIP table when the other woman bumped them. They pushed each other but were separated – until the woman confronted Kournikova again as she was leaving the nightclub.
"The woman came back over and threw a drink on Anna and her assistant," the source said. "The woman was definitely drunk."
"Anna said she wanted the woman kicked out, but then everything started to escalate and she and the woman started shoving and pushing each other," the source said.
The other woman grabbed Kournikova by the neck and pushed her into a wall before security broke them apart.
"Anna looked really shaken up," the source said. Kournikova was checked out at The Venetian hotel but didn't require further treatment, said an onlooker.
Kournikova's rep was unavailable to comment.
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