Eastbourne’s Johanna Konta survived a three-hour battle against Svetlana Kuznetsova to advance to the last eight of the singles in Rio.
Konta was already through to the third round and took on eighth seed Kuznetsova, a two-time grand slam champion, with a place in the quarter-finals at stake.
It was nip and tuck all the way in the second and third sets but after three hours and eight minutes it was 10th seed Konta who prevailed 3-6 7-5 7-5.
Having failed to serve out the match at 5-3 in the decider, the 25-year-old recovered from 0-40 at 5-5 before clinching victory on her fourth match point.
She said: “I’ve been very fortunate so far in my career that I’ve been a part of so many spectacular matches.
“That definitely ranks up there just because it’s my first Olympics. I feel pretty lucky and privileged that I get another chance tomorrow.”
Konta will fight on two fronts after it was confirmed on Tuesday that she and Jamie Murray will be Britain’s entrants in the mixed doubles.
Andy, the silver medallist four years ago with Laura Robson, also entered with Wimbledon champion Heather Watson but her ranking of 66 left them 18th in the entry list, which is decided on combined rankings, for the 16-team draw.
Andy said: “The plan was always that Jamie was going to play with Jo. Jamie is a way more experienced doubles player than me.
“Jo is playing well, too, so they have a good chance of winning a medal. There’s an outside shot that me and Heather could potentially get in as well.
“But I’ve played a lot of tennis, it’s been really hard to prepare for here after the French and Wimbledon. I hadn’t played a match on a hard court for five months.
“Playing every day two matches in a row is not easy on this surface and in these conditions. So that made more sense.”
The draw paired Jamie and Konta with American duo Bethanie Mattek-Sands and Jack Sock.
Asked if, like Andy, she might have preferred just to focus on the singles, Konta said: “Is that a serious question? We’re at the Olympics. Who wouldn’t want to be a part of all the events possible?”
Konta will next face either second seed Angelique Kerber or Australia’s Sam Stosur, and she insisted thoughts of a medal are far from her mind.
“I’m just as far as I am close,” she said. “I just played an incredibly long match and right now it’ll be about me recovering the best I can and being prepared for tomorrow.”