USA TODAYSam Stosur tops Kristina Mladenovic at Citi Open for 500th match victoryUSA TODAYWASHINGTON (AP) — Sam Stosur recorded her 500th career victory Tuesday, moving into the second round of the Citi Open hard-court tournament by beating Kristina Mladenovic 6-2, 6-2. Stosur is a 31-year-old Australian who won the 2011 U.S.