Qualification for the IRB World Sevens Cup quarter-finals is tight; to guarantee a berth Wales must also defeat Chinese Taipei in the tie on Saturday and then squeeze past South Africa later the same day.
Wales could still qualify for the Cup quarter finals if they finish second. Yet only the top two second-placed sides go through to the Cup and to be one of these Wales would have build up a healthy points differential.
The reason for what seems a more complicated qualifying process is that Hong Kong has maintained its tradition of being a 24-team tournament, now divided into six pools of four.
Wales played in the opening two tournaments in Dubai and George and then took time out. Their re-entry into the circuit will give three players - Pontypridd and Blues outside half Dai Flanagan, Bedwas and Dragons centre James Lewis and Wrexham-born Llanelli and Scarlets flanker Rob McCusker - a first taste of the IRB World Series.
Tonga have proved awkward rather than skilful opponents but there is little question that they battle hard. However,Wales have good sevens skills and the right amount of pace, particularly so in Scarlets' Alec Jenkins and Penzance flyer Rhodri McAtee.
Interest will surround the Blues fullback Jamie Roberts, who missed Dubai because of injury, and the form of the now more muscular scrum half Wayne Evans. These two players could make a huge impact in Hong Kong.
The atmosphere this weekend is expected to be as highly charged as usual. This is the prestige event; the one that attracts the biggest following. This is the stage on which Wales could make an impact if they can keep their focus and cope with hot and humid conditions that Hong Kong traditonally throws up.
Wales Sevens squad
Jonathan Edwards (Capt, Llanelli RFC)
Lee Beach (Ospreys)
Wayne Evans (Blues)
Dai Flanagan (Blues Academy/Pontypridd RFC)
Alec Jenkins (Scarlets Academy/Llanelli RFC)
James Lewis (Dragons Academy/Bedwas RFC)
Rhodri McAtee (Penzance)
Rob McCusker (Scarlets)
James Merriman (Gloucester)
Richard Mustoe (Ospreys)
Jamie Roberts (Blues Academy/Cardiff RFC)
Tal Selley (Ospreys)