Jo-Wilfried Tsonga, the 2011 Vienna champion, lost ground in his race for a place at the ATP year-end championships after going down 6-4, 3-6, 6-1 to Lukas Rosol on Thursday in the Austrian Open second round.
The Frenchman who started the week on provisional ninth for the eight-man finals next month in London, all but admitted that his chances are gone after tasting defeat against the Czech player, four days after losing the Shanghai Masters final against world number one Novak Djokovic.
"Today, I didn't play good enough to win. I tried, but things did not work for me."
The former Australian Open finalist said that he can accept the fact that he will likely not earn a spot in London, though he could well make the trip as a well-paid alternate.
"I'm not sad, three weeks ago I was 24th in the race," said a player who only began his season in mid-March due to injury. "It's important for me to take every point that I can.
"But I won't be playing until Paris Bercy (starting a week from Monday), I now have some time to rest. I just hope to be more consistent in 2016 and stay healthy."
The defeat strengthened the hand of David Ferrer, who spent a mere 62 minutes in delivering a crushing 6-1, 6-1 defeat to fellow Spaniard Guillermo Garcia-Lopez to stay in the thick of the London points chase on eighth with the last two spots in the field still to be claimed.
The top seed who lost the final here a year ago at the Stadthalle to British number one Andy Murray, is now on the brink of a place in the English capital.
Kei Nishikori, who stands seventh, is not playing this week. He leads Ferrer by 455 points, with a title at the revitalised Vienna event now worth 500 points.
But the Japanese later withdrew with an existing shoulder injury from next week's Basel event and could be in qualifying danger due to his inactivity.
"Of course I have pressure, but I'm in a good position," said Ferrer, winner of four titles this year who missed three spring-summer months with an elbow injury. "There is more pressure on the others.
"I played a much better match today after adapting to the conditions. I had no mistakes, but I'm only in the quarter-finals. To earn the title I have to win three more matches."
The Spaniard won with five aces to the same number of double-faults for Garcia-Lopez, with Ferrer breaking five times.
Ferrer, 33, takes a perfect 15-0 record over Fabio Fognini into his quarter-final after the Italian eighth seed advanced 6-1, 6-4 against Czech Radek Stepanek
South African second seed Kevin Anderson used 15 aces to good advantage in a 6-7 (4/7), 6-3, 7-5 comeback win over Czech Jiri Vesely to next take on American Steve Johnson, a 6-4, 6-7 (7/9), 6-4 winner over Poland's Jerzy Janowicz.