Shaun Edwards says he will be "unbelievably disappointed" if Wales do not win their next three games and secure a World Cup semi-final place.
Wales will book a last-eight spot by beating Fiji in Oita next Wednesday.
Uruguay are then their final group opponents four days later, with the Six Nations champions red-hot favourites to finish top of Pool D.
France or Argentina are potential quarter-final opponents if they progress, while a semi-final appearance would equal best World Cup performances of 1987 and 2011.
After defeating Australia and Georgia to take charge of their pool, Wales are already being backed by many pundits as semi-finalists – at least.
"We have been in the semi-final once, as a coaching group," Wales defence specialist Edwards said.
"I think the two games we've just won, if we don't win our next three, I will be unbelievably disappointed.
"Obviously, if you do win your next three, you are in the semi-finals and back to where we were in 2011.
"After the Australia game, and we knew we had a break (in Otsu), it was about rest, switching off and trying to even forget about rugby a little bit to recharge the batteries.
"We are in Test week now, we are fully focused on Fiji, and we saw a team last night that is a huge threat.
"We are excited about playing a Test match first and foremost, and obviously the fact it is a World Cup and we could top our group makes it even more special."
Wales, though, know from experience just how dangerous Fiji can be, losing a 2007 World Cup pool game to them in Nantes that meant they were dumped out of the tournament.
They gained World Cup revenge for that defeat four years ago, yet Fiji's second-half destruction of Georgia on Thursday showcased a team packed with blistering try-scoring talent.
"They are definitely one of the teams who you don't want to break structure too much," Edwards added.
"I am hoping we put in an 80-minute strong defensive performance.
"I was pleased with huge aspects of the game against Australia – we were under huge amounts of pressure in the second-half – but we have not put an 80-minute performance in yet at the World Cup.
"There are a lot of tactical things we will try to do. We won't change our defensive system much. We want to cut time down for opposition nines and 10s.
"We will look to tackle in twos as much as possible, and then if they get their hands free you have to squeeze in around those off-loads and trail the support runners.
"We are under no illusions about what they will bring. They are very well-coached and organised, and have that X-factor.
"They are definitely one of the best sides in the world at sevens, so that will cross over."