Susan Egelstaff secured Great Britain's first win of the competition with a comfortable 21-15, 21-10 defeat of Slovenia's Maja Tvrdy.
In a match watched by Prince Charles at Wembley Arena, the Scot, ranked 38, overpowered the world No 89 in 34 minutes.
It was a perfect Olympic debut for 29-year-old Egelstaff, who missed four months of the qualifying campaign with a serious leg injury. She now has a two-day break to prepare for her second match in Group H against 12th seed Sayaka Sato of Japan.
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Egelstaff's performance gave the crowd plenty to cheer at the start of the second session after the morning had brought defeat for medal hopefuls Chris Adcock and Imogen Bankier in the mixed doubles.
Egelstaff dominated from the outset. There were some lengthy rallies early on, but her lofted serves helped to establish control. Eight successive points took her into a 19-10 lead and, despite a few unforced errors, she closed out the first set comfortably. She then maintained her dominance, covering the court superbly.
Egelstaff had feared she would miss the Games after shattering her thigh bone in October.
The Glaswegian said: "I was so nervous going on because it was such a big thing, but I settled down in the second set and managed to pull away. I really enjoyed it. It was an excited kind of nerves. It's so nice just to be here. It was looking very unlikely a few months ago.
"I'm not expecting to get a medal but the target in the meantime is just to play well. It's nice not having too high expectations. It's not getting any easier with Sato next. I have beaten her before, but obviously she's a much better player now."
Egelstaff felt the home crowd also played a role in her victory.
"Quite often when I play nobody is watching," she said. "It makes you concentrate and not give away stupid points. I am pleased with the way I played. "
Compatriot Bankier and her partner Adcock, meanwhile, failed to capitalise on a fine start in the opening set of their Group A match against Russia's Alexandr Nikolaenko and Valeria Sorokina, and 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, today face Germans Michael Fuchs and Birgit Michels, before a match against top seeds Zhang Nan and Zhao Yunlei.
Bankier, 24, said: "We had a great start. I think we were playing well and the reaction we got when we went into the arena helped us. We felt very positive going into the first set and won that quite comfortably but, like us, they had a game plan and they managed to combat ours.
"The third set was back and forwards but we just couldn't get that run we needed. We're extremely disappointed but we've got to get over it and move on, get ready for the next game."
Adcock, 23, added: "Obviously we're very disappointed. But it is a group stage and two wins can still get us to the next stage."