Andy Murray has accepted that he will have to do things the hard way if he is to reach the semi-finals of the ATP World Tour Finals, having lost 6-4 6-4 to Kei Nishikori in his opening match.

Murray was far from his best as he sunk to defeat to the Japanese, with the Scot now having to win against both Roger Federer and Milos Raonic if he is to progress from the group stages in London.

The former Wimbledon and US Open champion said after a first loss in four matches against Nishikori: “It’s harder to qualify when you lose your first match, that’s pretty obvious, but unlike the other events you still have a chance to go through.

“If this were anywhere else, I would be out of the tournament. Now I need to win my next two matches more than likely and win them well if I want to go through, so I’m definitely going to have to play better.”

Murray had gone into the action at the O2 Arena in fine form after title wins in Shenzhen, Vienna and Valencia in recent weeks, but now has it all to do, starting against Raonic on Tuesday, after the Canadian lost his opener to Federer 6-1 7-6.

Raonic and Murray have met on four previous occasions and the Canadian holds a 3-1 winning record, including a 4-6 7-5 6-3 win in Indian Wells in their only meeting this year.

Murray can be backed at 13.00 to recover and top Group B and is 17.00 to win the ATP World Tour Finals for the first time in his career.