Johanna Konta slogged for over three hours to a 3-6 7-5 7-5 victory against Svetlana Kuznetsova, while Andy Murray made a confident bid to defend his Olympic title on Tuesday with a second round 6-2 6-1 victory over Juan Monaco.
Konta went a set down to the world no.10 Kuznetsova despite a promising start, losing 6-3 in just 38 minutes. And she was broken again in the first game of the second set, but managed to hold her next serve.
Though it looked bleak for Konta, she fought back to save four break points in her last two service games, to take the second set 7-5 in a tiebreaker and reassert her presence in the game.
Kuznetsova finally broke Konta in her third service game to take a 3-2 lead in the third set, but Konta was not about to give up without a fight and broke back immediately. Going on to hold her serve then break the Russian again, Konta was serving for the match at 5-3 after the most epic of battles.
So very close to losing her edge Konta hit back with some blistering forehand shots to bring the game to deuce. Another battle ensued before Konta hit it long to allow Kuznetsova back in the game.
The Russian went on to hold her serve and it became nail-bitingly close once again as Konta began to show the strain of the battle, but from 15-30 down she came back to hold her serve with an ace.
As it began to look as if Konta might give it all away, an unforced error by Kuznetsova handed the elated Brit victory on her fourth match point to book a place in the quarter-finals.
Now ranked 13th in the world, Konta is the first British woman to progress beyond the second round of the women's singles event since the sport was reinstated at the Olympics in 1988.
On the basis of his performance on Tuesday, Murray will also make the last eight. The Scot took an early lead against Monaco, and looked to have the first set pretty well wrapped up, only for the Argentinian to break back with some great forehands.
But he was outclassed by Murray who took the first set against Monaco on his third set point with ace to win 6-2.
Murray then romped to victory in the second set to win 6-1 and set up a third round meeting with either Italy's Fabio Fogini or France's Benoit Paire, and with David Ferrer out of the contest after a shock defeat in the second round, Murray's title defence looks ever closer.
Andy Murray (GBR) of United Kingdom in action
Image credit: Reuters
Men's Singles second Round
Evgeny Donskoy (RUS) bt David Ferrer (SPA) 3-6 7-6 7-5