World tennis number one Novak Djokovic is through to the fourth round of the Miami Masters, the defending champion easily seeing off fellow Serb Viktor Troicki, 6-3 6-4.
Auckland champion David Ferrer of Spain eased past France's Julien Benneteau in straight sets while Nicolas Almagro edged Fernando Verdasco 6-3 6-4 in an all-Spanish battle.
11th seeded Argentine Juan Martin Del Potro beat Croatian Marin Cilic 6-3 7-6.
Belarusian world number one Victoria Azarenka struggled with Slovakia's Dominika Cibulkova, needing a tiebreak after losing the first set badly before taking the third set to reach the quarter-finals 1-6 7-6 7-5.
Also through to the last 16 in Miami in the women's draw are three former world number ones, with fourth seed Caroline Wozniacki of Denmark ending Belgian Yanina Wickmayer's run 7-6 6-0, 10th seeded American great Serena Williams beating sixth seeded Australian Samantha Stosur 7-5 6-3 and second seed Maria Sharapova prevailing over Ekaterina Makarova in an all-Russian tussle, 6-4 7-6.
Germany's Sabine Lisicki bowed out to China's Li Na 3-6 6-4 6-2.