Roger Federer and Stanilas Wawrinka have reached the fourth round of the Men's Singles event of the Miami Open Tennis tournament. The 18th times grand slam winner Swiss beat Juan Del Potro of Argentina 6-3, 6-4 in the third round.Federer will face Roberto Batista in the next round. Batista beat Sam Querrey of USA 3-6, 6-2, 6-3. Top seeded Wawrinka beat Malek Jaziri 6-3, 6-4 in the third round. Wawrinka will clash with Alexander Zverev in the next round.19 year old Zverev beat John Isner 6-7, 7-6, 7-6. In the Women's Singles former world number one Venus Williams of USA has reached the quarter finals.