Wales romped to a 31-12 win over the Cook Islands in their opening match after leading 19-5 at the break thanks to tries by Gareth Davies, Ifan Evans and Jevon Groves. Rhys Jones knocked over a couple of conversions while the Islanders only response was a five pointer by Koiatu Koiatu.
Evans raced over for his second try early in the second half with Adam Vardey responding with a converted try shortly afterwards but Richie Pugh scored on the stroke of full time to ensure Wales got off to the perfect start.
The big hitting Americans had now answer to Wales's second match in the third leg of the 2010/11 HSBC Sevens World Series.
The match was even poised at halftime with Wales hanging on to a slender 12-7 lead with Rhys Jones converting his own try and Evans racing over after Miles Craigwell had scored for USA.
But it was once way traffic in the second spell as Wales raced over for four tries with Lee Rees grabbing two and Alex Cuthbert and Evans finishing the job.
Pool favourites England proved a different proposition however. Wales were still in the match at the break with Cuthbert's converted try seeing England hold a 14-7 advantage.
But three second half tries by England condemned Wales to a 33-7 defeat and ensured they finished top of the pool while Wales finished second.
Cup quarter finals
England v Argentina
Fiji v Samoa
Australia v South Africa
New Zelaand v Wales