20-year-old Serbian Ana Ivanovic (aka Golden Girl #2) has signed potentially the biggest racquet endorsement deal in the history of tennis. According to CNBC sources “it’s a four-year deal that could hit eight figures if Ivanovic is ranked No. 1 for about half the deal.” Ivanovic begins the season ranked fourth in the world but will rise to a career-high ranking of No.3 on the Sony Ericsson WTA Tour when the new rankings come out on Monday.