"We knew we had to come out today and show what we could do. It was not just for ourselves but for all the people watching," said Wales sevens skipper Jonathan Edwards.
He added, "We reflected on our performance against Tonga and knew what we had to do today. Tonga surprised us and basically denied us ball. Sevens is all about keeping the ball.
"We're still in with a shout of making the Plate quarter finals but it's all about how we do against South Africa. We'll go out with all guns blazing. We know what South Africa can do and we've come close to toppling them before."
It was Alec Jenkins who gave Wales the perfect start with two tries before Richard Mustoe and Lee Beach touched down to give Wales a 26-0 lead at half-time.
Thereafter it was just a matter of how many points Wales could amass. Tal Selley started the second-half charge followed by two scores from skipper Edwards, before Dai Flannigan touched down, leaving flier Rhodri to sign off Wales's effort with a final contribution for a 61-0 demolition job.