The United States posted two wins on the opening day of the USA Sevens to book a place in the Cup quarter-finals in the fifth round of the IRB Sevens World Series.
The hosts launched their campaign with a 52-12 win over Japan.
Zack Test then scored one of the best tries of the day in a 19-7 victory over Portugal that ensured they would progress.
They will be joined by defending champions and series leaders South Africa, who are chasing a third successive title in Las Vegas, New Zealand and Fiji, who all won their opening two matches.
With the conclusion of pool matches and quarter-finals scheduled for Saturday, New Zealand sit atop of Pool A going into the second day after a gritty 15-5 victory over Samoa.
Also in Pool A, Fiji survived a late scare from Wales, who surged back from from 28-0 down before falling 28-24.
Earlier, a Scott Curry hat-trick highlighted New Zealand's 40-7 win over Wales as the defending series champions picked up where they left off in Wellington last week.
In the battle of the Pacific islands Fiji scored six unanswered tries in a 36-0 win over Samoa.
The race for a quarter-final berth in Pool B remained open, with each side posting one win apiece.
Canada pulled off the first major upset of the tournament with a 15-12 win over England.
A brace of tries from Argentina's Franco Sabato helped secure the Pumas' 19-14 win over Kenya.
England beat Argentina 19-17 and Kenya edged Canada in a thriller 22-21.
South Africa joined the United States in advancing from Pool C, opening their title defense with a 19-0 win over Portugal and following up with a 42-5 win over Japan.
Australia also appear headed to the quarter-finals after two wins in Pool D, but they must wait on a day two match against Scotland to confirm their place in the last eight.
Scotland rebounded from a 19-7 loss to France by scoring six tries in a 38-14 win over Brazil.
A first half brace to Pama Fou paved the way for Australia's 31-14 victory over France, which followed a 45-0 rout of Brazil.
Source: AFP