They beat Wales and Australia to finish second to England in Group B and cannot be caught in the overall standings.
England added a 10-7 win over Australia and 24-5 success over Wales to their 31-10 victory against Fiji.
England take on Scotland in Sunday's quarter-finals while Fiji face France.
South Africa will face Argentina in the last eight after winning all of their pool matches while the United States will play New Zealand.
Wales lost to Australia, Fiji and England to finish bottom of Pool B on Saturday.
Scotland beat Kenya and Portugal and drew with France to come second to the French in Pool C.
Rugby sevens will feature for the first time at the Olympic Games later this year in Rio.

The net benefit is about £257m each year and takes into account the impact on public services such as the NHS.
In 2014, 34,670 students travelled from outside the European Union (EU) to study in Scotland.
But PwC said its research showed the overall experience of foreign students is compromised by the UK's complex immigration system.
The auditors claim this also has an impact on their ability to secure work following graduation and has called on the UK government to improve its data collection around migration.
The PwC calculation does not include the value to Scotland of non-fee spending (including accommodation, travel and leisure) by students from outside the UK, or non-fee spending by EU students, most of whom do not have to pay tuition fees.
Lindsey Paterson, from PwC in Scotland, said: "With a lot at stake, not just for the Scottish and UK economy but for the future growth and prosperity of our higher education establishments, it's clear that more needs to be done to inform and improve immigration policies and targets."
She added: "Our Scottish universities and colleges are competing in a global marketplace and it's vital that government supports them in attracting the brightest academic talent not just from here in the UK, but from the EU and further afield.
"International students not only help to broaden our own students' vision and perspective in the classroom but have a major economic impact through their fees and consumer spending."
PwC has recommended that the UK classify students as temporary visitors, not migrants, as is the case in Canada and Australia. It claims this will make it easier for international students to work in the UK post-graduation.

Sarries beat Tigers in the final round of pool matches, and will play Aaron Mauger's side at Allianz Park again.
Quins, seventh in the top-flight, go to an Exeter side hoping to reach the final for the third time in a row.
Welsh regions Dragons, Scarlets, Ospreys and Cardiff all failed to make it into the last four.
The Anglo-Welsh Cup did not take place last year due to the 2015 Rugby World Cup.
The semi-finals will take place between 10-12 March, with the final to be staged at the Twickenham Stoop.
Fiji lost to hosts England in their first game at the London Sevens but bounced back to reach the quarter-finals and retain their World Sevens Series title in the process.
[NEXT_CONCEPT]
Overseas students boost the Scottish economy by about £312m each year, according to figures from auditors PwC.
[NEXT_CONCEPT]
Reigning champions Saracens will host Leicester, with Exeter at home to Harlequins in an all-Premiership semi-final line-up in the Anglo-Welsh Cup.