Defending champions Fiji thrashed Wales 42-7 in a repeat of last year's final, on the first night of the Hong Kong Sevens on Friday.
The Dragons took an early lead through Samuel Cross, before Fiji's Samisoni Viriviri opened the floodgates with the first of six tries in their Pool A contest.
Coach Ben Ryan said that his Fiji team had "a look in their eye" on the pitch and added "They want this. We didn't start too well but at least this one's out the way after a long day waiting."
New Zealand, who took to the field with something to prove after finishing fourth in the Tokyo round of the tournament last weekend, pounded Scotland 33-0, while the South Africans enjoyed a 31-7 win against France as they continue to pursue their maiden title success in Hong Kong.
England's James Rodwell, winning his 50th cap, scored one of his team's three tries against old rivals Argentina, helping them to a hard-fought 19-12 victory. There were also wins for both the USA against Samoa and the Canadians, who saw off Portugal.
Elsewhere, Australia proved too good for Spain, while the ruthless Kenyans posted seven tries in a 41-0 rout of hapless Sir Lanka.
The pool matches continue on Saturday, with Fiji meeting Sri Lanka and Kenya, South Africa taking on Spain and Australia, and New Zealand facing Samoa and the USA.