However, the Cherry Blossoms will have their work cut out against a Tongan side who were competitive in all of their pool games - against New Zealand, Argentina and Ireland.
Tonga Head Coach Fe'ao Vakata said: "We had talked about our second half performances before the Ireland game because in our first two matches against New Zealand and Argentina, we played well in the first half and lost our concentration in the second.
"That also happened against Ireland so it is an area we need to work on. The tackling was not good enough against Ireland and we conceded some soft tries."
Tonga prop Mosa'ati Afu said: "We have had some excellent support from family and friends in the crowd and it's good to see and hear them in the game. This competition has been a good learning experience for us and we are hoping to win our remaining games."
Neither Fiji or USA won a game in the pool sages of the tournament and both will be keen to at least move into the final of the 13th-16th place phase this weekend.
USA Coach Salty Thompson said: "We're trying to raise the standard of USA rugby and I think we have already achieved a great deal. I hope we can play even better against the Fijians and maybe get our first win."
Fiji Captain Jese Cirikisuva added: "The boys are very disappointed because we didn't perform against Canada. We didn't settle at all well in the first half and it took some time in the second before we really started to play. There are certainly some areas we need to improve on before we play our next game."
Wednesday 18 June - The Racecourse, Wrexham
Tonga v Japan - kick-off 5pm
USA v Fiji - kick-off 7pm