In poker, Anna Kournikova is a name some players give to the Ace-King hand, especially in hands where it doesn't hit on the board. This is a knock on the tennis player, who is primarily more known for her good looks than her effectiveness on the court.
e.g. Player 1 - "I knew I shouldn't have made such a big pre-flop raise, darn AK off suit"
Player 2- "It can often be a gamble with the ol Anna Kournikova!"