Wales secured a vital victory against closest rivals Japan in their bid to remain in the top 14 of the World Rugby Sevens Series.
Richie Pugh's side entered the penultimate round of the series in 14th place, three points ahead of Japan.
But the attempts of Captain Luke Treharne, Afon Bagshaw and Joe Goodchild saw Wales secure a 17-0 quarterfinals victory challenge victory.
They face Scotland in the semi-finals later on Sunday.
Wales had lost to Australia and series leaders the United States before the victory over Spain in Saturday's pool matches.
Wales team: Luke Treharne (capt), Owen Jenkins, Ethan Davies, Cai Devine, Afon Bagshaw, Joe Jenkins, Joe Goodchild, George Gasson, Cameron Lewis, Dafydd Smith, Reuben Morgan-Williams, Ben Cambriani, Tom Rogers, Morgan Williams.