Andy Murray's chances of qualifying for the season-ending ATP Finals suffered a setback as he lost 2-6 6-1 6-2 to David Ferrer in the third round of the Shanghai Masters.
Murray, 27, made an impressive start, losing just four points on his serve in a brilliant display in the first set.
But as Ferrer upped the aggression, the British number one's second serve became less reliable.
The Spaniard, 32, now overtakes Murray in the 'Race to London' standings.
|Race to make ATP Finals|
|Murray is currently 10th in the race to reach the November ATP Finals - the top eight qualify for the season-ending event.|
|However, Murray might need to rise to seventh with the eighth spot going to a 2014 Grand Slam champion ranked between eighth and 20th. Croat Marin Cilic, who won the US Open, is currently ranked sixth.|
The top eight players in the ATP rankings qualify for the World Tour Finals in November, and Murray would have moved to within five points of a top-eight spot had he beaten the world number five.
Instead, Ferrer rises to ninth in the rankings on 3,715 points, while the Briton drops a place to 10th on 3,655 points - although not all hope of playing at the 02 Arena is lost for Murray.
However, the defeat means he is more likely to compete at the Valencia Open, which starts on 20 October and provides 500 ranking points to the winner. Should the Briton not play in Spain, he might have to win the Paris Masters at the end of October to compete in London.
|Russell Fuller, BBC tennis correspondent|
|"Although not yet terminal to Murray's World Tour Finals hopes, this defeat will do little for his confidence - he still hasn't beaten a top eight player this season. The further Ferrer goes this week, the harder Murray's task will become, as both the Spaniard and Milos Raonic will need to be behind the Scot when the Race to London concludes in Paris. Murray may now decide he should play in Valencia the week after next. If he doesn't, then the maths may not look too clever when he rolls up in the French capital."|
The match had started brightly for Murray. The 11th seed played impeccably in the first set, stepping in from the baseline and overpowering his opponent as he broke in the opening game.
He secured a double break and after just 36 minutes the first set belonged to the Scot, with a place in the quarter-finals seemingly a matter of routine.
But Ferrer fought back and the former champion faltered, winning just three of a possible 18 points on his second serve in the second and third sets.
"I didn't play as well up at the net as I had been since I've been here in Asia, maybe that's why I was slightly reluctant in the third set to come forward as much," said Murray.
Ferrer, who lost to Murray in the final of this tournament in 2011, will play world number one Novak Djokovic in the last eight.
The top seed was pushed all the way by the unseeded Mikhail Kukushkin of Kazakhstan, who played inspired tennis at times before eventually falling 6-3 4-6 6-4.
"He pushed me to the last point," admitted the two-time defending champion. "He deserves credit for how he played. Some shots were incredible.
"It was definitely the toughest match I've had so far in China. I'm really glad I managed to stay mentally tough."