Hosts USA are on course to clinch their first ever tournament win on home soil after staging a thrilling comeback in the Cup quarter-finals of the USA Sevens in Las Vegas.
Mike Friday's side came back from 19-0 down against Argentina to win 21-19, producing one of the spectacles of the tournament so far. USA are into the semi-final stages for the third year in a row and face series leaders South Africa in the Cup semi-finals.
On the other side of the draw Fiji will play New Zealand. "I think we showed that we can be down but we're never out," said USA captain Madison Hughes.
"We are going to have to play some great team during a tournament but we just have to stick together and keep fighting."
Neil Powell's South Africa outfit have won three of the last four tournaments on the world series and had to produce a big performance against Australia to secure their semi-final spot.
A late try from speedster Rosko Specman proved crucial as the Blitzboks won 17-14. Back-to-back series champions and Olympic Gold medallists Fiji faced Canada in their quarter-final and delivered a clinical five-try performance, two coming from Apisai Domolailai, to win 31-12 against head coach Damian McGrath's side.
In the final Cup quarter-final of the day, New Zealand outclassed an England side that only recently made the final at the HSBC Sydney Sevens, winning 19-0.
The Challenge Trophy semi-finals will feature France v Kenya and Scotland v Samoa.
South Africa went unbeaten in their pool following two wins on day one of the tournament against Canada (26-7) and France (31-0), and a convincing 21-7 victory over Wales on day two. Considering the Blitzboks have only lost seven pool matches in two years, it's no surprise they went into the match against the Welsh determined to keep a perfect record in Las Vegas. Cecil Afrika, Chris Dry and Siviwe Soyizwapi scored the tries and helped keep Neil Powell's side top of the Pool.
Canada's close 24-21 win over Wales on day one gave them a fighting chance for qualification on day two, which they seized with both hands when they put 21 unanswered points against France in their final pool match to secure them second place.
England continued their blistering start from day one, where they beat Chile (31-5) and Samoa (12-7) with a stunning pool match against USA in front of a packed out Sam Boyd stadium. Charged up by the crowd, Mike Friday's USA side came out of the blocks quick with tries from Martin Iosefo and Perry Baker and a conversion from Madison Hughes making it 12-5 at half-time, despite Dan Norton's supreme solo effort.
USA added a quick try early in the second half through Ben Pinkleman, but England rallied scoring two tries in quick succession through Richard de Carpentier and Tom Mitchell before Tom Bowen burst down the left wing to steal victory from the hosts.
Argentina stole the show in Pool C, topping the group for the first time since Singapore in April last year. A 43-0 win over Russia on day one and 14-14 draw with Kenya set up a showdown with New Zealand, a team they had only ever beaten eight times in 74 encounters. Tries from Fernando Luna and Nicolas Menendez and a conversion from Gaston Revol gave Santiago Gomez Cora's side a healthy lead at half-time.
However, one of the tries of the day was about to take place thanks firstly to Vilimoni Koroi who performed an incredible trick pass from the sideline, and finally DJ Forbes who powered his way over the line from distance with a huge fend on the Argentinean defence. Isaac Te Tamaki added another score and it was left up to Koroi to slot the extras, but due to the wind whipping around the stadium the ball passed just wide.
Fiji's perfect run of pool matches from day one continued on day two with a hard fought 24-17 win over Australia, with tries from Mesulame Kunavula, Kalione Nasoko and two from Samisoni Viriviri. Scotland, following a disappointing two losses on day one, salvaged three more points with a 33-7 victory over Japan.
(Kick-off is local time – GMT -8)
13th place semi-finals
Japan v Chile – 11:24
Wales v Russia- 11:46
Challenge Trophy semi-finals
France v Kenya – 12:08
Scotland v Samoa- 12:38
Australia v Argentina – 13:00
Canada v England – 13:22
South Africa v USA – 13:44
Fiji v New Zealand – 14:06
Day Two Results:
England 0-19 New Zealand
Fiji 31-12 Canada
Argentina 19-21 USA
South Africa 17-14 Australia
Challenge Trophy quarter-finals
Samoa 31-7 Russia
Scotland 28-21 Wales
Kenya 21-19 Chile
France 24-14 Japan
South Africa 21-7 Wales
France 0-21 Canada
England 24-17 USA
Samoa 17-12 Chile
New Zealand 10-12 Argentina
Russia 10-12 Kenya
Australia 17-24 Fiji
Japan 7-33 Scotland
With thanks to World Rugby