Following on the coat-tails of the women's event which thrilled the crowds in Rio, the men's competition in the Rugby Sevens got underway on Tuesday with drama and tries aplenty. 

Each of the 12 teams played two group matches on the opening day of competition, with Japan's shocking 14-12 over New Zealand the standout result of the day.

Rugby Sevens in full-flow at the Rio Olympics (image via: worldrugby.org)

Elsewhere at the Deodora Stadium, South Africa, Fiji and Team GB all won both of their matches, while hosts Brazil were beaten twice despite putting up a fight in both fixtures. 

Fijians lead Pool A following wins over South American pair

With the pressure of a nation on their shoulders, Ben Ryan's Fiji made a solid start to their campaign with wins over Argentina and Brazil on day one. 

Starting up against Brazil, Fiji ran in six tries in a 40-12 triumph, which included a brace of scores for Toulon winger Josua Tuisova. Samisoni Viriviri also crossed for a try, while World Series Player of the Year Jasa Veremalua starred with two tries of his own. 

Jasa Veramalua attempts an offload against Argentina (image via: worldrugby.org)

Then in their second fixture, Kitione Taliga's late double was enough for the Fijians to see off Argentina 21-14, with Jerry Tuwai's last-ditch tackle on Axel Muller securing the victory. 

Earlier in the day, Argentina overcame three yellow cards to beat the USA 17-14 with Matias Moroni scoring the winner after the siren, with the United States nilling the Brazilians in the other fixture, and scoring tries of their own through Carlin Isles, Folau Niua, Maka Unufe and New England Patriot, Nate Ebner

GB impress with two wins, while Japan knock-off Kiwis

In the result of the day, Japan repeated the tricks of their 15-a-side team, beating New Zealand 14-12 in a stunning result. After Akira Ioane had put the Kiwis five points ahead, a try by Kameli Soejima followed by gallant defence saw the Japanese claim a famous scalp.

Japan celebrate a famous victory over New Zealand (image via: worldrugby.org)

New Zealand hit back in their second fixture, beating Kenya 28-5 thanks to scores from Ioane, Agustine Pulu and Lewis Ormond after Collins Injera had given the Africans an early lead. 

The leaders of the pool overnight however, are Team GB who claimed two impressive victories on day one. Britain scored five tries through Dan Norton, Phil Burgess, Dan Bibby (2) and Mark Bennett to see off the Kenyans 31-7, before a James Rodwell double set the wheels in motion for a win over Japan.

From 14-0 up, Great Britain were pegged back by the Japanese through tries from Lomane Lemeki and Katsuyuki Sakai, before Marcus Watson looked to have won the game with a late, late score. That was not the end of the drama though, and Lemeki scored his second try, only to see Sakai miss the resulting conversion to give Britain a 21-19 win. 

Over in Pool B, South Africa lead the way following two wins, ahead of France and Australia in joint second, with Spain back in third.