`` All in all World No . four Maria Sharapova stays on course for third successive Miami title . Czech will next face 15th seed Tommy Haas in the last 16 of hard-court event . Maria Sharapova , four times a runner-up at Key Biscayne , also through to round four . Indian Wells winner will next play Serbian world No . 22 Klara Zakopalova .
World No . four Maria Sharapova stays on course for third successive Miami title . Czech will next face 15th seed Tommy Haas in the last 16 of hard-court event . Maria Sharapova , four times a runner-up at Key Biscayne , also through to round four . Indian Wells winner will next play Serbian world No . 22 Klara Zakopalova .