Wales coach Warren Gatland is confident his side's fitness and attacking strength will lay to rest the ghosts of past upsets at the hands of Fiji.
South Africa's 13-5 defeat of Samoa on Friday means Wales are likely to progress even if they lose on Sunday.
"If our set piece is good, if we're on the front foot, and defend well, we're good enough to win," Gatland said.
"We've got a nice balance with some size in the back line, some real attacking ability," he added.
"So it's about us and having the confidence to go out to perform and play well."
In the 2007 World Cup, Wales lost 38-34 to Fiji as they were eliminated in the final game of the group stages, precipitating Gareth Jenkins' departure as coach, and in the 2010 autumn internationals under Gatland they drew 16-16 with the Pacific islanders in Cardiff.
Wales have also suffered World Cup defeats at the hands of Fiji's island neighbours Samoa, in 1991 and 1999.
But Gatland says Wales' improved physical prowess should avoid a repeat of the failings that led to last year's draw.
"The negatives of that game were lack of collision dominance," he said.
"The analysts said we were about 69% of collision dominance against Fiji last year and we are about 95% in the last three games, so that's made a massive difference to us - the amount of attention we've done at the contact, the breakdown area."
Gatland has made seven changes for Sunday's final Pool D match against Fiji in at Waikato Stadium, resting wing Shane Williams.
They are on course to finish second in their group behind South Africa and go through to a potential quarter-final against Ireland - unless they lose to Fiji by at least 39 points, with Fiji scoring four tries and Wales failing to score four.
WALES TEAM TO FACE FIJI
Lee Byrne; George North; Scott Williams, Jamie Roberts; Leigh Halfpenny; Rhys Priestland, Mike Phillips; Gethin Jenkins, Huw Bennett, Adam Jones, Bradley Davies, Luke Charteris, Ryan Jones, Sam Warburton (c), Toby Faletau. Replacements: Lloyd Burns, Paul James, Alun Wyn Jones, Andy Powell, Lloyd Williams, Stephen Jones, Jonathan Davies