TWICKENHAM, London - England will have to do it the hard way if they are to become the first country to win their home event on the World Series this season despite going through pool play unbeaten on day one of the London Sevens.

The Red Roses will face World Series champions South Africa in the quarterfinals on Sunday, after the Blitzboks were stunned by the USA 24-12 in their final pool game to finish second in their group. South Africa have won five of the nine tournaments on the circuit this season.

England started strong in front of a raucous crowd full of energy at Twickenham, as they recorded a comfortable 28-7 win over Spain in their first game, where Dan Norton scored his 50th try of the campaign.

The hosts were then pushed to the brink by both Australia and Samoa, before a Norton brace in the former, and an Alex Davis score in the dying stages of the latter saw them complete Saturday three from three.

"We showed tremendous fight," Norton told ESPN. "It's been showing from all of the season. The team spirit and effort to work hard and fight for each other is what we are all about and that's what's been getting us all these wins and pushing us in the right direction.

"We've had some good games against [South Africa] throughout the year. They're obviously a very aggressive, strong team, you have to be able to front up but be smart about it at the same time. It's going to be a humdinger."

Kalione Nasoko of Fiji is tackled by Nathan Hirayama of Canada. Charles McQuillan/Getty Images for World Rugby

Canada provided one of the shocks of the day in the opening match with an upset 22-19 win over Fiji.

The Olympic gold medallists from Rio bounced back, thrashing Japan 61-5, but a 27-21 loss to rivals New Zealand saw them miss out on a quarterfinal spot for the first time this season.

London Sevens quarterfinals USA vs. Australia (10:58 a.m. BST) New Zealand vs. Scotland (11:20 a.m. BST) England vs. South Africa (11:42 a.m. BST) Argentina vs. Canada (12:04 p.m. BST)

New Zealand, who need victory in London to extend their run of winning at least one tournament on the World Series for the last eight years, will face 2016 London Sevens winners Scotland in the quarterfinals.

The Scots snuck into the last eight courtesy of a higher points differential to France, who they lost to in the final match in Pool B.

Argentina topped the group after two wins to set up a quarterfinal date with Canada.

The first quarterfinal on Sunday gets underway just before 11:00 local time with the USA up against Australia.