Owen Williams raced over for four tries on day one in Port Elizabeth.
Wales let slip a golden opportunity of claiming a major scalp on day one of the Nelson Mandela Bay South Africa Sevens in the pool decider against Fiji.
After securing victories over Zimbabwe and Portugal, Wales jumped out to a 14-0 lead against the world series pacesetters but Fiji showed why they are such a force to be reckoned with in the abbreviated game to roar back with five unanswered tries to record a 29-14 triumph.
Wales will begin day two in the Cup quarter-finals with a match against Samoa who topped Pool A with wins over England, Argentina and USA. Paul John's men have played the South Sea Islanders once this campaign, winning the Plate Final 26-15 in the opening leg of the HSBC World Series in Australia two weeks ago.
Earlier Owen B Williams also scored twice in both of Wales' victories - 42-7 against Zimbabwe and 34-7 over Portugal - to set up the crucial decider against Fiji.
Despite the defeat to Fiji, Wales Sevens head coach Paul John was delighted to see his young side reach the main draw for the second day's action.
He said, "It was a great achievement by the side to get through to the quarter finals for the third week on the trot. It was fully deserved as I thought they played well all day.
"We got two good wins against Zimbabwe and Portugal - who won the FIRA competition in the summer. Once again we pushed Fiji all the way, going 14-0 up. With the opportunity to go further ahead we made a couple of unforced errors and they showed what a great team they are to fully capitalise.
"We now have another opportunity tomorrow against Samoa who topped their group. It would be a great achievement to go at least one step further tomorrow. This side has already proved they are a match for anyone when they believe in themselves."
As the countdown continues for RWC2015, Tournament Chief Executive Debbie Jevans visited the Millennium Stadium to discuss preparations for the eight matches and reveal the positive news that 100,000 tickets for games at the home of Welsh rugby have sold in the last seven days.
Jason Harries is targeting a first win on the World Series circuit this season with Wales. The series returns to action this weekend in Dubai where Harries is part of a team hoping to build from its efforts in round one in October.
Wales skipper Jevon Groves says his side have addressed a few points from Gold Coast and aim to 'hit the ground running' in the next two rounds of the World Series, kicking off with this weekend in Dubai before heading off to South Africa next week.
Wales Sevens manager Steff Thomas is hopeful his side can build from a quarter-final spot in the opening round of the World Series in Australia when his side take part in the forthcoming double header in Dubai and South Africa.