The road to London has been arduous for Andy Murray. 

Today under the unforgiving glare of the lights of a packed 02 Arena, the Scot received confirmation that he still has some way to travel before he can prosper once more at the elite level.

His 6-4, 6-4 defeat to Kei Nishikori of Japan took just one hour and 35 minutes. The 27-year-old from Dunblane  will, however, have spent much of last night reflecting precisely on the lessons learned by a dispiriting setback in the Barclays ATP World Tour finals.

Murray may now have to defeat Milos Raonic and Roger Federer to progress to the semi-finals. This challenge would test Murray in his pomp. He was far from that today, perhaps finding the journey to London had left him with little fuel to race away from Nishikori, despite having taken the initiative when he broke the Japanese player in the first set.

The manner in which he squandered this advantage was worrying in that Murray was immediately broken and ended that game with a double fault. Nishikori, who should have been on the ropes, was instead revitalised.

The world No.5 laid his opponent low with compact ground strokes, good movement and an ability to adapt to the Murray strategy of forcing him to play high off either side. He served poorly, however, and Murray, one of the best counter punchers in the game, will have been devastated at his inability to profit, particularly on the second serve.

However, Nishikori, given that Murray reprieve in the first set, almost strolled away with the second, breaking Murray at the first opportunity and racing into a 3-0 lead. The rest of the set was instructive in that it showed that 2013 Wimbledon champion retains his technique, his stubborness and his appetite for a fight. He could have slipped gently off into the London night, but he broke back and showed tantalising glimpses of the player who has won two grand slams and an Olympic gold.

But if the body has healed one year after back surgery, there remain flaws. He is not yet battle-hardened against the top players. His resurgence to take three titles in the climax to the season included a spell where he defeated Grigor Dimitrov, David Ferrer, Marin Cilic and Jo-Wilfried Tsonga. Nishikori, who has won four tournaments this season and defeated Novak Djokovic to reach the US Open final, was simply too good for him today. Although he lost to Cilic at Flushing Meadows, he is a better player.

There are no causes for dismay for Murray, however. This, after all, was his defeat to the 24-year-old from Japan and if he was occasionally outmanoeuvered and generally outplayed there is no suggestion that these are permanent traits.

Murray will first examine a serve that was never formidable. His second serve was routinely plundered with Murray only winning 27 per cent of points with the ball in his hand for the second time. Nishikori, whose serve was dismal, won 50 per cent of points on his second serve.

On such margins are top-class matches decided and Murray was right to berate himself for this failure in his press conference. However, he was correct in charting the recent progress that saw him become an unlikely contender in London.

"The beginning of the year was hard because I didn't feel like I was playing particularly well," he admitted. "I feel like I've played well for most of the events since the French Open. I've had fairly consistent, decent results."

His first aim was simply to win matches, then it was to win tournaments. Now he has to take that next step and play and beat the big boys. He knows that involves being at his highest level for an entire tournament, which for a grand slam victory must include seven five-set matches.

"At the beginning of the year it was hard, because before I had my surgery, I was consistently there. When you come back and you aren't quite there, that's obviously frustrating," he said.

This frustration has been replaced with a belief that he can make it back to the top table. The defeat against Nishikori will not have dented that faith but it has emphasised that the Murray has to regain a resilience in the tough moments.

The Japanese has enjoyed his best season, winning four tournaments and reaching the final of the US Open but he needed that Murray dip in the first set to set him on the road to victory. There was also a moment in the second set, when Murray fought from 0-3 to 4-4, that one almost believed that the tenacious British No.1 could find a way out of a perilous spot. This proved forlorn as Nishikori broke him in the last game.

This ruthlessness, this ability to find a way to prevail against the very, very good on a regular basis has deserted Murray. He is certain that it will return. "I'm sure I'll be good next year," he said.

He will need to be highly proficient tomorrow and on Thursday to keep this season alive. The full resurrection of Murray, however, may have to wait until 2015.