Wildcard Venus Williams defeated former world number one Ana Ivanovic 6-7 (4/7), 6-2, 6-2 in the fourth round of the ATP/WTA Miami Masters hardcourt tournament on Monday. Williams advances to the quarter-finals where she will face fifth seed Agnieszka Radwanska who rolled over Garbine Muguruza Blanco of Spain 6-3, 6-2. Venus follows her sister into the quarters after Serena defeated Australian Samantha Stosur 7-5, 6-3 in an earlier fourth round match on Monday.