Andy Murray insisted there was no need for alarm bells despite losing his opening ATP World Tour Finals match in straight sets to Kei Nishikori.
Murray arrived in London after a demanding six-week schedule that saw him play 23 matches and secure three titles en route to climbing up the world rankings to book his spot in the season-ending event.
However he was unable to maintain his form, struggling with his serve as the world number five, who was making his ATP Finals debut, took the first set 6-4 before racing into a 4-1 lead in the second.
Murray, who twice saved five match points to win titles against Tommy Robredo in recent weeks, came to life to draw level at 4-4.
But Nishikori recovered to win the next two games and wrap up the match at the O2 Arena.
Murray will now face six-time champion Roger Federer and in-form Milos Raonic as he tries to secure one of the two semi-final places from Group B – and he was determined to give it his best shot.
"It's harder to qualify when you lose your first match, that's pretty obvious,” he said.
"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.
"I didn't serve well enough. He was able to dictate a lot of points, especially behind my second serve.
"That was the part of the match where he had the upper hand. That was the difference.
"You need to try to forget about today, work on some things tomorrow, and hopefully play better on Tuesday."
© Sportsbeat 2014