Wales had to overcome monsoon conditions and stubborn opposition before getting their Cathay Pacific/Credit Suisse Hong Kong Sevens campaign off to a winning start against Japan.
The newly crowned World champions ran out 14-5 victors but had to come from behind before taking the honours at Hong Kong Stadium.
The Japanese scored first through Kilryong So but the Welsh struck either side of half-time, first through Ifan Evans and then James Lewis. A new look Wales side attempted to spread the ball but the slippery conditions made free-running rugby a lottery.
With 30 points on offer to the Cup winners in Hong Kong, the 24-team event could go a long way to deciding the outcome of the Series.
With only one side guaranteed a place in the Cup quarter finals from each pool, the onus is on every team to score as many points as possible in Hong Kong.
That means Wales must go out first thing tomorrow and rack up the points up against China in their second pool game before facing the in-form English. China were walloped 54-0 today by England and Paul John's side are fully aware the red rose army pose a major obstacle if they are to progress to the knock-out stages.
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.