New Zealand have qualified for the inaugural women's rugby competition at next summer's Olympic Games in Rio de Janeiro despite slipping to a shock defeat against Spain on the opening day of the latest World Sevens Series leg in London.

The Kiwis have been virtually unbeatable in recent years, winning both editions of the Series since it was first introduced in 2012-2013 and having claimed 37 consecutive victories heading into the latest event.

After a regulation opening win over Brazil that all changed, however, in stunning circumstances at The Stoop as their European opponents showed a stubborn refusal to giving up, eventually forcing a 19-15 victory thanks to a last gasp try by Spanish captain Patricia Garcia.

Garcia admitted afterwards that it was a massive win for Spanish rugby, while New Zealand counterpart Sarah Goss conceded that Spain were better on the day.

“Spain put up a good show like they always do," she said

"They are a quality side and unpredictable."

Goss' team fought back with a 24-0 win over France to reclaim top spot in the group and confirm their Rio participation, but will now realise plenty of hard work lies ahead and they are by no means certain of gold.

Spain were rewarded for their plucky efforts by finishing second in Pool A to set up a quarter-final against Australia tomorrow, while England will be the next challenge for the All Blacks after a heavy 31-0 loss to Canada consigned them to second place in Pool B.

Canada, meanwhile, who laboured to a victory over Russia before finding their best form against South Africa and the English, will now face Russia again for a place in the last four.

United States against France will complete the lineup at The Stoop stadium, with the competition to conclude tomorrow as action begins at nearby Twickenham Stadium in the latest round of the men's World Series.

With one round to go after this weekend - in Amsterdam next weekend - and the top four teams at the end of the Series qualifying for Rio, Canada, Australia and France are currently in poll positions for the other three places, although United States, England and Russia all remain in with a chance.