<p>Reigning US Open champion and second seed Andy Murray blasted nine aces en route to a 7-6 (7/3), 6-3 victory over Bulgarian Grigor Dimitrov in the third round of the Miami Masters.<br /><br /></p>.<p>Murray, who won this event four years ago, needed one hour and 54 minutes to oust the 29th-seeded Dimitrov.<br /><br />Murray said he got off to a slow start but soon figured out how to cause problems for his opponent.<br /><br />"I was leaving the ball a bit short. Once I started to improve my depth a bit I made it tough for him and he started to make mother mistakes after that," Murray said.<br /><br />Dimitrov, last year's runner-up to Novak Djokovic, would have faced a tougher task had not the 21-year-old lost his composure when serving for the first set at 5-3.<br />Dimitrov double-faulted three times to allow Murray to break back and the Scot duly prevailed in the tie-break.<br /><br />It is the second time in as many tournaments that Dimitrov has cracked when serving for a set against a top-ranked player, serving up four double faults when he led world number one Djokovic 5-3 in the third round at Indian Wells.<br /><br />"He probably got a little bit nervous, and that helped me," Murray said.<br />Murray, who committed 22 unforced errors to Dimitrov's 38, will face Italian Andrea Seppi in the fourth round, the 16th seed having beaten experienced Brazilian Thomaz Bellucci 7-5, 4-6, 6-2.<br /><br />Meanwhile, eighth-seeded Frenchman Richard Gasquet rolled over 28th-seeded Russian Mikhail Youzhny 6-3, 6-4 and 10th-seeded Spaniard Nicolas Almagro beat Belgian David Goffin 6-3, 6-4. Gasquet faces Almagro in the fourth round.<br /><br />Also, sixth seed Jo-Wilfried Tsonga, of France, cruised past Finland's Jarkko Nieminen 6-3, 6-3 as Canada's Milos Raonic withdrew from the tournament with strep throat just moments before his match against Sam Querrey. In the women's draw, China's Li Na set up a quarter-final against world number one Serena Williams with an error-strewn 7-6 (8/6), 6-2 win over giantkilling Spanish teenager Garbine Muguruza.<br /><br />The 31-year-old Li is playing in her first tournament since suffering an ankle injury in January's Australian Open final.<br /><br />Williams also struggled having to come from a set down to win 2-6, 6-4, 6-2 against Slovakia's 13th seed Dominika Cibulkova.<br /><br />Williams, who is bidding for a record sixth Miami title, admitted she had not been at her best and at 4-1 down to Cibulkova in the second set and staring defeat in the face she had had to pull herself together.<br /><br />"I was struggling mentally, I was making so many errors," said Williams, who regained the number one spot in Doha in February but has not played since.<br />"I could not pull myself together. Someone (a fan) kept telling me to relax and I listened to him."<br /><br />Li - the 2011 French Open champion and two-time Australian Open finalist - made 39 unforced errors, including four double faults, and allowed her 19-year-old opponent to battle back to 5-5 in the first set having led 5-1.<br /><br />Even at 6-1 in the tiebreker Li faltered as 73rd-ranked Muguruza, who had claimed the scalps of the seeded Caroline Wozniacki and Anastasia Pavlyuchenkova in previous rounds, fought back to 6-6.<br /><br />However, fifth-seeded Li pulled herself together to take the next two points and the set, before wrapping up victory in the second set.<br /><br />Meanwhile, defending champ Agnieszka Radwanska defeated American Sloane Stephens 4-6, 6-2, 6-0 to reach the quarter-finals.</p>
<p>Reigning US Open champion and second seed Andy Murray blasted nine aces en route to a 7-6 (7/3), 6-3 victory over Bulgarian Grigor Dimitrov in the third round of the Miami Masters.<br /><br /></p>.<p>Murray, who won this event four years ago, needed one hour and 54 minutes to oust the 29th-seeded Dimitrov.<br /><br />Murray said he got off to a slow start but soon figured out how to cause problems for his opponent.<br /><br />"I was leaving the ball a bit short. Once I started to improve my depth a bit I made it tough for him and he started to make mother mistakes after that," Murray said.<br /><br />Dimitrov, last year's runner-up to Novak Djokovic, would have faced a tougher task had not the 21-year-old lost his composure when serving for the first set at 5-3.<br />Dimitrov double-faulted three times to allow Murray to break back and the Scot duly prevailed in the tie-break.<br /><br />It is the second time in as many tournaments that Dimitrov has cracked when serving for a set against a top-ranked player, serving up four double faults when he led world number one Djokovic 5-3 in the third round at Indian Wells.<br /><br />"He probably got a little bit nervous, and that helped me," Murray said.<br />Murray, who committed 22 unforced errors to Dimitrov's 38, will face Italian Andrea Seppi in the fourth round, the 16th seed having beaten experienced Brazilian Thomaz Bellucci 7-5, 4-6, 6-2.<br /><br />Meanwhile, eighth-seeded Frenchman Richard Gasquet rolled over 28th-seeded Russian Mikhail Youzhny 6-3, 6-4 and 10th-seeded Spaniard Nicolas Almagro beat Belgian David Goffin 6-3, 6-4. Gasquet faces Almagro in the fourth round.<br /><br />Also, sixth seed Jo-Wilfried Tsonga, of France, cruised past Finland's Jarkko Nieminen 6-3, 6-3 as Canada's Milos Raonic withdrew from the tournament with strep throat just moments before his match against Sam Querrey. In the women's draw, China's Li Na set up a quarter-final against world number one Serena Williams with an error-strewn 7-6 (8/6), 6-2 win over giantkilling Spanish teenager Garbine Muguruza.<br /><br />The 31-year-old Li is playing in her first tournament since suffering an ankle injury in January's Australian Open final.<br /><br />Williams also struggled having to come from a set down to win 2-6, 6-4, 6-2 against Slovakia's 13th seed Dominika Cibulkova.<br /><br />Williams, who is bidding for a record sixth Miami title, admitted she had not been at her best and at 4-1 down to Cibulkova in the second set and staring defeat in the face she had had to pull herself together.<br /><br />"I was struggling mentally, I was making so many errors," said Williams, who regained the number one spot in Doha in February but has not played since.<br />"I could not pull myself together. Someone (a fan) kept telling me to relax and I listened to him."<br /><br />Li - the 2011 French Open champion and two-time Australian Open finalist - made 39 unforced errors, including four double faults, and allowed her 19-year-old opponent to battle back to 5-5 in the first set having led 5-1.<br /><br />Even at 6-1 in the tiebreker Li faltered as 73rd-ranked Muguruza, who had claimed the scalps of the seeded Caroline Wozniacki and Anastasia Pavlyuchenkova in previous rounds, fought back to 6-6.<br /><br />However, fifth-seeded Li pulled herself together to take the next two points and the set, before wrapping up victory in the second set.<br /><br />Meanwhile, defending champ Agnieszka Radwanska defeated American Sloane Stephens 4-6, 6-2, 6-0 to reach the quarter-finals.</p>