Andy Murray moved into the fourth round of the Sony Ericsson Open without stepping on court after opponent Milos Raonic pulled out with an ankle injury.

36124 - Murray gifted place in fourth round

Murray, who beat Colombian Alejandro Falla on Friday to secure his first win in Miami since his 2009 victory, was due to play the No. 26 seed on the Grandstand court at Crandon Park.

However, the Canadian, who was forced to retire from his doubles match on Saturday after spraining his right ankle, offered his opponent the walkover before the players were due to take to the court on Sunday. Murray awaits either Gilles Simon or Jurgen Melzer in the fourth round.

"Unfortunately I couldn't play today with my hurt ankle, time to rest up and get ready for clay," Raonic posted on his Twitter page.

But while Murray made serene progress into the last 16, No. 7 seed Tomas Berdych was dumped out by world No. 101 Grigor Dimitrov, who claimed his first win over a top-ten opponent with a 6-3 2-6 6-4 win.

Next up for the Bulgarian is No. 9 seed Janko Tipsarevic, who avoided an upset at the hands of Alexandr Dolgopolov 6-4 5-7 6-2. The winner of Tipsarevic's fourth-round clash against the highly-rated Dimitrov could face Murray in the quarter-finals.