Fiji, South Africa and Great Britain finished as the only unbeaten teams, but it was Japan who stole the headlines on day one at the Deodoro Stadium with one of the biggest upsets in sevens history with victory over New Zealand.
Japan had never beaten New Zealand, but Kameli Soejima's try tied the scores and Katsuyuki Sakai slotted the conversion to put them 14-12 ahead. The All Blacks Sevens were given one final chance to attack from a Japan lineout error, but their defence held firm to spark the celebrations.
They nearly caused another shock in the second session against Great Britain after Lomano Lemeki's last-gasp try, but Sakai couldn't add the conversion and Team GB escaped with a 21-19 victory.
With only three teams unbeaten, all eight quarter-finals places are still up for grabs and will be determined after the final pool matches on Wednesday. The sessions gets underway at 11:00 local time (-4 hrs BST) with some intriguing match-ups, including Great Britain against New Zealand.
Argentina snatched victory from the jaws of defeat at the death when Matias Moroni touched in the corner for a 17-14 win over the USA despite three yellow cards. Axel Muller and Fernando Luna had given Los Pumas Sevens a 12-0 lead but a penalty try and Danny Barrett score then put USA ahead in the Pool A opener before Moroni intervened.
Brazil then sent the home crowd wild against Fiji when the Sancery twins, Felipe and Daniel, combined down the wing to send Felipe Claro over for the opening try – only the third they’ve ever scored against the Pacific islanders. They couldn’t hold on until half-time though as Jasa Veremalua scored to give Fiji a 7-5 lead.
The series champions took control in the second half, Viliami Mata dominating the restarts as Fiji scored tries through captain Osea Kolinisau, powerhouse Josua Tuisova (2), Samisoni Viriviri and Veremalua. Brazil kept battling and were rewarded with the final score as Gustavo Albuquerque dotted down with time up.
There were to be no tries for Brazil in their second match against the USA Eagles Sevens, who were too strong for their hosts with Folau Niua and NFL Super Bowl winner Nate Ebner touching down in the first half and then rugby's fastest man Carlin Isles and Maka Unufe following suit late in the second to leave Mike Friday's side third, behind Argentina on points difference.
Fiji then ensured their place on top of Pool A with a hard-fought 21-14 victory over Argentina in the day's final match, two second-half tries from replacement Kitione Taliga proving the difference. Tuisova had given Fiji an early lead but the spirited Los Pumas Sevens hit back through Franco Sabato and Santiago Alvarez to ensure a tense final few minutes. Argentina'sAxel Muller had a chance to get his side back into the match in the dying seconds but a last ditch tackle from Jerry Tuwai stopped Muller in his tracks.
Just as in the women’s competition it was a French player who scored the first Olympic try in the men’s sevens in captain Terry Bouhraoua, although unlike Camille Grassineau he helped himself to a hat-trick amid a 24-point haul in their impressive 31-14 win over Australia.
South Africa got off to a winning start with a 24-0 victory over Spain, the final team to qualify for the men’s competition as repechage winners. Cecil Afrika scored their first two tries before speedster Seabelo Senatla and Philip Snyman dotted down.
Australia had the perfect start when Cameron Clark scored from the kick-off, but two tries in quick succession from Marcos Poggi gave Spain an unlikely lead. Jesse Parahi edged Australia ahead once more and further tries from John Porch and Con Foley sealed a 26-12 win that leaves them second.
The two unbeaten sides in Pool B went head-to-head in the second session, but France had no answer to the power of South Africa with Justin Geduld, Kwagga Smith and captain Kyle Brown scoring the tries in a 19-0 victory. France sit third in the table, behind Australia on point difference, with a match to come against Spain on Wednesday.
Great Britain came out determined to lay down a marker and raced into a 24-0 lead at half-time with tries from Dan Norton, Phil Burgess, Dan Bibby and Mark Bennett. Kenya showed greater intensity after the break but could only manage a try from Billy Odhiambo, before Bibby wrapped up the 31-7 win with his second try.
Japan then evoked memories of RWC 2015 as they stunned third seeds New Zealand with a 14-12 victory with tries from Teruya Goto and Kameli Soejima. Japan looked to have thrown away their chance of a first ever win over the All Blacks Sevens when they overthrew at a lineout with time up, but their defence held firm to spark the celebrations.
Even more worrying for New Zealand coach Gordon Tietjens than the defeat was the fact that Sonny Bill Williams and Joe Webber were forced off injured, the double Rugby World Cup winner ruled out of the competition with a partial Achilles tear and replaced by Sione Molia.
Japan came with a kick of another surprise, Katsuyuki Sakai unable to convert Lomano Lemeki’s try long after the hooter had sounded to enable Great Britain to escape with a 21-19 victory. Two early James Rodwell tries had put Team GB in control, but Lemeki and Sakai had Japan back level at 14-14 until Marcus Watson broke clear to score.
New Zealand and Kenya both knew victory was a must and it was the African side who scored first through the series all-time leading try-scorer Collins Injera. It was the All Blacks Sevens who emerged victorious, though, after tries from Akira Ioane, Augustine Pulu, Lewis Ormond and a penalty try in a 28-5 win.
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