Chris Adcock and Imogen Bankier will start the second day of competition at London 2012 knowing defeat could effectively end their badminton campaign.
Great Britain's mixed doubles pair arrived at Wembley Arena with realistic medal ambitions after reaching the final of the World Championships at the same venue last year.
But their Olympic debut turned sour as they failed to build on a superb start and lost 14-21 21-9 21-18 to Russia's Alexandr Nikolaenko and Valeria Sorokina.
With a match against top seeds Zhang Nan and Zhao Yunlei to come on Tuesday, they now realistically need to beat Germany's Michael Fuchs and Birgit Michels in their second Group A match to keep hopes alive.
Glaswegian Bankier, the 24-year-old daughter of Celtic chairman Ian, said: "We know we can play better than that, so we have got to recover, get over this one. We'll start afresh. We'll look at some video and do our best to come up with a plan with the coaches and do it all again."
After entering the arena to a huge roar from the home crowd, Adcock and Bankier, the world number 10s, were quickly into their fast-paced, attacking stride.
Bankier was dominant at the net and Adcock punished anything lofted to set up the possibility of a quickfire victory. It was not to be though as the world number 15 Russians changed tactics and slowed the tempo to take charge in the second game.
The third was more evenly contested and the pairs traded points early on but the Russians then turned a 14-12 deficit into a 16-14 lead and went on to win.
There has been controversy already this week with organisers making dramatic revisions to the playing schedule on the eve of competition, much to the annoyance of some players. A number have complained but, while Adcock and Bankier may have had good reason to feel aggrieved after initially being told they would not play Saturday, they did not use it as an excuse.
Bankier said: "It's not too bad. We found out quite early so we had a day to prepare."