Tennis: Murray world number one after Raonic walkover

The walkover will see Murray, 29, move to the top of the rankings for the first time in his career after replacing long-time incumbent Novak Djokovic.

The Scot's climb to the ATP rankings' summit caps a remarkable year which has seen him win a second Wimbledon crown and mount a successful defence of his Olympic title in Rio.

Raonic said he had suffered a muscle tear in his right leg in his previous match, sending Murray through to face John Isner in Sunday's final.

"This morning I had trouble waking up and getting out of bed. So I went to sort of clear any serious diagnosis," said Raonic, who hurt himself in Friday's quarter-final win over Jo-Wilfried Tsonga.

"Did some tests. Did an MRI half an hour ago, let's say. They found that I have a tear, Grade 1 tear in the right quad.

"Unfortunately, I'm not able to compete against Andy today in the second semi-final."

Murray had needed to reach the final to supplant Djokovic at the top following the Serb's defeat to Marin Cilic in the last eight.

But he didn't need to hit a single ball as Raonic announced his withdrawal in a hastily-arranged press conference.

Murray will be confirmed as the new number one when the latest rankings are released on Monday.

He will meet Isner as he targets a maiden Paris Masters title after the big-serving American toppled Cilic 6-4, 6-3 in the first semi-finals.

Isner, who also reached the last four in 2011, broke the ninth seed at 4-all before serving out for the first set.

Cilic sealed his place at the Tour Finals in London this week and then snapped a 14-match losing run against Djokovic, but the Croat couldn't maintain that level against Isner.

The American seized control again at 3-3 in the second set and inflicted his first defeat on Cilic in seven attempts with another break of serve.