Five years ago, in the shadow of Christ the Redeemer, Puerto Rico’s Monica Puig shocked the world by topping the podium after arriving in Rio de Janeiro as a heavy underdog. History could well be about to repeat itself at Tokyo 2020.

There was a masterclass of giant-killing on day three of the Olympic Tennis Event as Belarusian Aryna Sabalenka, 2020 Roland Garros champion Iga Swiatek and Petra Kvitova, a bronze medallist in Rio, all crashed out of the tournament.

With a host of seeded players succumbing to defeat, the field opens for the likes of Naomi Osaka and Elina Svitolina, who both advanced to the third round and are now a win away from the quarter-finals.

However, there may well be other pretenders to the throne after surprise wins for Croatia’s Donna Vekic, Paula Badosa of Spain and Belgian Alison van Uytvanck – a trio who, on paper at least, might well have been unfancied pre-tournament.

Vekic, whose best result at a Grand Slam is reaching the last eight at the US Open in 2019, went the distance and ultimately dispatched Sabalenka, who is seeded No. 3 here, on Centre Court at Ariake Tennis Park.

The 25-year-old, who held her nerve in the decisive set to prevail 6-4 3-6 7-6(3), will now face Kazakhstan’s Elena Rybakina, who defeated Sweden’s Rebecca Peterson 6-2 6-3, in round three.

“It is really good, really satisfying [to beat Sabalenka],” said world No. 50 Vekic. “Winning 7-6 in the third set is always great. She’s playing really good tennis this year so I’m sure this win will give me a lot of confidence.

“I don’t want to think about my chances of a medal. I’ve played two tough, long matches. I’ve come here I would say not 100 per cent prepared. I’m still struggling a little bit with my knee. I’m just taking it one day at a time. I will try to recover and get ready for tomorrow.”

Van Uytvanck, meanwhile, who is ranked No. 59 in the world, progressed at the expense of two-time Grand Slam champion Kvitova, recovering from a set down to defeat the Czech 5-7 6-3 6-0.

“She’s a legend in our sport,” said Van Uytvanck, who underwent knee surgery in February. “She’s an absolute great player and it’s an honour to share the court with her – that’s what I told her at the net. I think what she has done for women’s tennis is incredible.

“I hope that I can maybe some day achieve the same things she has achieved. I’m proud of myself with what I did on court today and the level I reached.

“After the surgery it has been tough to come back to competition. I lost a couple of matches in a row, then I had the grass season which gave me good confidence. Then to come here and beat Petra is one of the biggest wins I ever had.”

Another Grand Slam champion in the form of Garbine Muguruza, who continued her own quest for gold with a commanding 6-3 6-0 victory over China’s Wang Qiang, awaits Van Uytvanck in the third round.

“I’m playing Muguruza next, another great champion in our sport,” added Van Uytvanck. “It’s going to be tough but in the top 100 a lot of girls can play. It’s who has the better mentality and confidence. I hope I can play another good match and let’s see what happens.”

World No. 29 Badosa, who was crowned Roland Garros girls’ champion in 2015, was also in scintillating form as she sprung a surprise by downing Swiatek 6-3 7-6(4). Another with a Roland Garros backstory, Argentina's Nadia Podoroska, who reached the semi-finals in Paris last year, will be her next opponent after overcoming ROC’s Ekaterina Alexandrova.

While a host of seeded players are falling all around her, Svitolina continues to advance through the draw, menacingly perhaps, although she once again required three sets as she downed Ajla Tomljanovic of Australia 4-6 6-3 6-4.

“The ice bath is waiting for me, definitely,” joked Svitolina. “To be fair, I started not bad, 2-0 up, but then everything went downhill for me. I was playing really bad, I was a bit slow and I didn’t feel my game at all.

“Maybe it’s because of yesterday’s match [against Laura Siegemund] but in the end I was just trying to find my rhythm, move my feet a bit quicker and adjust. I just had to fight and try to find my game.”

Standing between Svitolina and a place in the quarter-finals is Maria Sakkari of Greece, who overcame Serbia’s Nina Stojanovic 6-1 6-2.

Elsewhere in the women’s draw, Roland Garros champion Barbora Krejcikova defeated Canadian teenager Leylah Annie Fernandez, with Belinda Bencic of Switzerland next up after she defeated home favourite Misaki Doi.

Another Czech to make progress was Marketa Vondrousova, who ousted Romania’s Marketa Buzarnescu 6-1 6-2 to set up a showdown with No. 2 seed Osaka, conqueror of Switzerland's Viktorija Golubic.

Roland Garros runner-up Anastasia Pavlyuchenkova powered past Anna-Lena Friedsam 6-1 6-1 and will now take on Spain’s Sara Sorribes Tormo, who accounted for Fiona Ferro of France.

It was the end of the road, however, for another Spaniard as Carla Suarez Navarro succumbed to Karolina Pliskova, who will now face Italy’s Camila Giorgi after she beat ROC’s Elena Vesnina in straight sets.

A different tale unfolded in the men’s draw, however, as only one seeded player in action on day three – Italy’s Lorenzo Sonego, who lost out to Nikoloz Basilashvili of Georgia – failed to make the next round.

A Golden Slam remains a possibility for world No. 1 Novak Djokovic following his 6-4 6-3 triumph against Jan-Lennard Struff of Germany, while No. 2 seed Daniil Medvedev also advanced at the expense of India’s Sumit Nagal.

There were also victories for seeded players Alexander Zverev, Pablo Carreno Busta, Fabio Fognini and Alejandro Davidovich Fokina over Daniel Elahi Galan, Marin Cilic, Egor Gerasimov, and John Millman respectively.