"The first day of the London tournament is crucial," said coach Treu. "If we're not 100 per cent focused on the task at hand we can make life very difficult for ourselves.
"We have to learn from our mistakes, as well as those of other teams who have stumbled over the last hurdle. That is why we're going over to Britain with the aim of getting 40 points, not just the 13 we need to win the series.
"It's been a tough season," added Treu. "In winning three tournaments we had to overcome very strong teams like Fiji, England, New Zealand and a resurgent Kenya.
"Psychologically it's been one of our toughest seasons to date. We've never been in this situation - going into the final two tournaments with an opportunity to clinch the series."
Wales's hopes have been boosted with six of the World Cup winning squad selected. Assistant coach Gareth Williams is hoping to finish the season with two solid showings.
"Unfortunately we haven't always had consistently in team selection but we've shown that when we've got our strongest squad together we are a match for anyone. The World Cup proved that. Hopefully we can finish the season off in style," he commented.
IRB Sevens Series standings (with 2 rounds remaining)
South Africa 104
New Zealand 64