1:23 PM Defending champion powers into the last 16 of the Miami Open along with Kei Nishikori and Milos Raonic.
A struggling Rafa Nadal crashed out of the Miami Open in the third round, losing to Fernando Verdasco.
Scottish tennis star Andy Murray is just one win away from setting a new British record in the open era.
South Korean teen wins his first ATP Tour-level match at the Miami Open, stunning Marcel Granollers.
World No 1 Serena Williams practised for the first time since a knee injury forced her to withdraw last week.