Murray gets a walkover into Miami last 16

The world No 4, who beat Alejandro Falla in round two – his only match of the tournament so far after he received a first-round bye – will meet either 13th seed Gilles Simon or Jurgen Melzer next.

“Playing against an opponent the calibre of Andy at only 40 per cent fitness didn’t make much sense,” said Raonic. “Yesterday we finished an hour-long session and, just as I was moving back, I rolled my ankle.

“It wasn’t getting any better in the doubles and was painful with pretty much every movement this morning.

“It’s frustrating, but if I look at the big picture I can see things are going well. Obviously it would be more frustrating if things were going poorly.”

Roger Federer held off local wildcard Ryan Harrison to set up a third-round clash against twice former Sony Ericsson Open champion Andy Roddick while Serena Williams served her way into the fourth round on Saturday night.

While men’s No 1 Novak Djokovic and women’s second-ranked Maria Sharapova progressed easily, former No 1 and twice Miami winner Kim Clijsters fought hard and survived six match points before falling to fellow Belgian Yanina Wickmayer 6-4, 7-6 (7/5) in their third-round clash.

“It was a special win for me today because she was one of my idols growing up,” the 22-year-old Wickmayer said.

Australia’s US Open champion Samantha Stosur avoided an early exit by storming back after falling a set and 4-2 down to beat South African Chanelle Scheepers 2-6, 7-5, 6-2.

Federer, who has won 40 of 42 matches and six tournament titles since the 2011 US Open semi-finals, led his 19-year-old opponent 5-2 in the second set before Harrison extended him to a tiebreaker taken 7-3 by the Swiss for a hard-earned 6-2, 7-6 win.

“I felt like I had to win the match like three times at the end, so I was relieved to come through,” Federer said. “Beating an American in America is always a big deal, because this is where they usually play their very best.”

Djokovic eased past Marcos Baghdatis 6-4, 6-4 while Williams belted eight aces in an overpowering 6-2 6-1 rout of 21st seed Roberta Vinci of Italy. “I played okay” said Williams. “I can definitely do better but I haven’t played a lot.”

Williams, whose five Miami titles tie her with Steffi Graf for the record, said she was still hungry for more. “I need trophies,” she said. “I want to add more. There are records to break.”

In yesterday’s early action, Grigor Dimitrov advanced by upsetting No 7 seed Tomas Berdych 6-3, 2-6, 6-4 for his first win over top ten opposition at the tenth time of trying. Serbian ninth seed Janko Tipsarevic beat No 18 Alexandr Dolgopolov 6-4, 5-7, 6-2. In the women’s third-round, seventh seed Marion Bartoli eliminated Simona Halep 6-4, 7-6 (8/6) and 16th seeded Slovakian Dominika Cibulkova beat Zheng Jie 6-2, 6-0.