World number one Novak Djokovic made a winning start at the Miami Open, beating Britain's 87th-ranked Kyle Edmund 6-3, 6-3. The top seeded Serb, who is trying to join Andre Agassi as a six-times Miami winner, will face Portugal's Joao Sousa in the third round. Meanwhile, Roger Federer withdrew from the tournament just hours before his second-round match, citing a stomach virus. In the women’s competition, Australian Open champion Angelique Kerber advanced to the third round with a 6-1, 6-1 win over the Czech Republic’s Barbora Strycova.