Otsu - Wales coach Warren Gatland reckons it will be "a big psychological boost" if his side finish top of their Rugby World Cup group.
The Six Nations champions are currently unbeaten at Japan 2019 following wins over Georgia and Australia, albeit they had to withstand a fightback before seeing off the Wallabies 29-25.
A victory over Fiji in Oita on Wednesday would guarantee Wales a place in the quarter-finals and if they then beat Uruguay four days later they will finish the group stage on top of Pool D.
Should that happen, Wales will be up against the runners-up in a Pool C featuring England, France and Argentina in the last eight.
"If you win the group, it's a big psychological boost because you are playing a quarter-final against a team who would have lost a game in their pool," Gatland told WRU (Welsh Rugby Union) TV.
"I think psychologically it's quite important for us to win this group, win the next two games, and then to start thinking about our quarter-final opponent.
"We are pretty happy with two from two. The next two matches are very important," added the New Zealander, who will stand down as Wales coach after the World Cup.
Fiji come into the match on the back of a 45-10 rout of Georgia and Gatland said: "Fiji are going to be tough for us. They had a great performance against Georgia. They are very much a confidence side, so we will have to be on top of our game and be defensively strong at the set-piece.
"We've got a short turnaround of four days, so a lot of the players who haven't had any rugby will get an opportunity then," explained Gatland, looking to lead Wales to their first World Cup title.
"They will be chomping at the bit to play against Uruguay."
Fiji famously knocked Wales out of the 2007 World Cup in the group stage and assistant coach Stephen Jones, the Welsh fly-half in the side beaten 38-34 in Nantes, said: "From a personal perspective, I am fully aware of how good they are.
"We have got to make sure from an attacking element that when we have got the ball we keep the ball.
"It (2007) highlighted what Fijian rugby is all about.
"Give them space and time and they move the ball well, have an off-loading game and put you under pressure.
"They did that day and scored some wonderful tries."