Tokyo - Wales scrumhalf Gareth Davies said on Friday that the Six Nations champions had a score to settle in this weekend's Rugby World Cup semi-final against South Africa.
The Springboks broke Welsh hearts at the quarter-final stage in London four years ago after a stunning Fourie du Preez try five minutes from time.
But Davies, who was on the scoresheet himself in that stinging 23-19 defeat, warned that Wales had unfinished business against South Africa in Yokohama on Sunday (kick-off 11:00 SA time), despite winning their last four meetings and five out of the last six.
"We were quite unlucky to lose that quarter-final four years ago," he said as Wales look to reach their first World Cup final, where they would face either defending champions New Zealand or England.
"It was a good bit of skill by them at the end to score a try late on. We were devastated with that because we felt we deserved to win that game," added Davies, who is set to earn his 50th Wales cap this weekend.
"We feel like we owe them one - that will be in the back of our minds and hopefully we can get one over them this week."
Wales, who huffed and puffed to beat 14-man France 20-19 last weekend and book their place in the last four, have suffered a major blow with star fullback Liam Williams ruled out for the rest of the tournament after injuring his ankle in training.
Coach Warren Gatland named Leigh Halfpenny as his replacement among three changes with Jonathan Davies returning from injury at outside centre and Ross Moriarty coming in for the injured Josh Navidi (hamstring) at eight.
"It will be everyone's biggest games of our careers so far," said Davies.
"It's massive - we still feel like we've got another big performance in us. I don't think we've had one full 80-minute performance yet. We're going to have to have a good 80-minute performance to come away with an important win."
Captain Alun Wyn Jones has demanded Wales come out firing after struggling to put away France.
"We showed character and that needs to come to the fore," he said.
"We have the experience of that French week and how we came through the game. We are expecting a better performance and a sling-shot effect from that."
Wales topped Pool D after shading a heavyweight clash with Australia 29-25 on their way to their first World Cup semi-final since 2011, which they lost 9-8 to France.
Wing Josh Adams, who tops the tournament's try-scoring charts with five tries alongside South Africa's Makazole Mapimpi and Japan's Kotaro Matsushima, underlined the team's determination to keep alive their dream run in Japan.
"It's something that's never been done in Welsh rugby," he said, struggling to recall where he was when he watched that 2011 semi-final on television.
"I would've been 16, playing youth rugby for Pontyberem, and I'm sure I was watching that, with a lemonade of course, being 16. It feels like a long time ago."
"We've never reached a World Cup final," added Adams.
"I think the feeling we've all got is that this is probably our best opportunity in a long time to do that."
15 Willie le Roux, 14 S'bu Nkosi, 13 Lukhanyo Am, 12 Damian de Allende, 11 Makazole Mapimpi, 10 Handre Pollard, 9 Faf de Klerk, 8 Duane Vermeulen, 7 Pieter-Steph du Toit, 6 Siya Kolisi (captain), 5 Lood de Jager, 4 Eben Etzebeth, 3 Frans Malherbe, 2 Bongi Mbonambi, 1 Tendai Mtawarira
Substitutes: 16 Malcolm Marx, 17 Steven Kitshoff, 18 Vincent Koch, 19 RG Snyman, 20 Franco Mostert, 21 Francois Louw, 22 Herschel Jantjies, 23 Frans Steyn
15 Leigh Halfpenny, 14 George North, 13 Jonathan Davies, 12 Hadleigh Parkes, 11 Josh Adams, 10 Dan Biggar, 9 Gareth Davies, 8 Ross Moriarty, 7 Justin Tipuric, 6 Aaron Wainwright, 5 Alun Wyn Jones, 4 Jake Ball, 3 Tomas Francis, 2 Ken Owens, 1 Wyn Jones
Substitutes: 16 Elliot Dee, 17 Rhys Carre, 18 Dillon Lewis, 19 Adam Beard, 20 Aaron Shingler, 21 Tomos Williams, 22 Rhys Patchell, 23 Owen Watkin