Great Britain's badminton mixed doubles pair of Chris Adcock and Imogen Bankier failed to capitalise on a fine start as they were beaten in their London 2012 opener at Wembley Arena.
Adcock and Bankier raced ahead in the opening game of their Group A match against Russia's Alexandr Nikolaenko and Valeria Sorokina, but their opponents hit back to win 14-21 21-9 21-18.
The Anglo-Scottish pair, silver medallists at the World Championships at the same venue last year, must now bounce back quickly against Germans Michael Fuchs and Birgit Michels on Sunday.
Having entered the arena to a huge roar from the near sell-out crowd, the world number 10s made a superb start against opponents ranked five places below them. The Britons dominated the opening game, with Adcock continually punishing Nikolaenko for lifting too often by smashing down at Sorokina while Bankier took charge at the net.
Their fast-paced attacking style was well rewarded as they took the opening game in 17 minutes, but the Russians changed the tempo to control the second. Sorokina came to the fore as Bankier faltered and the loss of six successive points early in the game put the Britons on the back foot.
With the momentum lost, the Russians eased away to level the match but Adcock and Bankier recovered their poise in a tight final game. There was little to separate the two pairs but Adcock and Bankier had the edge until the loss of four straight points turned a 14-12 lead into a 16-14 deficit.
Nikolaenko and Sorokina did not relinquish their lead and went on to wrap up the match in 61 minutes.
With a match against top seeds Zhang Nan and Zhao Yunlei also still to come, Adcock and Bankier, who had realistic medal hopes, face a battle to reach the knock-out stages.
Adcock, 23, said: "Obviously we're very disappointed. We came here for a win and we didn't get it. But it is a group stage and know that two wins can still get us to the next stage. That is the positive of the day.
"We started really well and the crowd were brilliant but they adjusted their tactics and we were unable to combat that. The third game got a bit scrappy and they came out on top. Ideally we wanted to win every game and get off to a good start but now we have to go back, recuperate and prepare for the next two games."