Having come into the game on the back of a five-day turnaround, coach Warren Gatland's side were given the fright of their lives by a Fiji side who threatened to damage Wales hopes of escaping the "pool of death".
Despite back-to-back defeats at the hands of England and Australia, the Pacific Islanders not only put in a Herculean effort, but deserved more from a game that was in the melting pot until the final throes.
Working off a dominant scrum and playing with typical flair behind, Fiji can count themselves unlucky not to have taken a losing bonus point, at least, into their final game of the tournament, against Uruguay.
In the end, Wales held on for a 23-13 victory and with no further injuries of note. They will enjoy the nine-day build up to what could be a winner takes all contest for Pool A against the Wallabies in London.
Gatland said: "It was a tough encounter and we are delighted with the win. Given the tough turnaround we had, between England and tonight, we had to dig deep.
"There are some battered bodies but I think we are OK in terms of injuries. I do think there is some exhaustion too.
"Now we have got a nine-day turnaround and hopefully that will freshen up the boys.
"I think we need to work on a bit of scrum stuff, but I thought we were good at lineout and our line speed was good, too. I was a bit frustrated at the breakdown tonight, but we will have a look at that in due course."
Wales led at the interval 17-6 thanks to tries from scrum-half Gareth Davies (pictured) and hooker Scott Baldwin and seven points from the boot of fly-half Dan Biggar.
George North did touch down for a third try, but referee John Lacey disallowed the score after Bradley Davies had been caught on camera, grabbing Netani Talei around the neck. It was a tough 40 minutes for Bradley Davies who spent 10 minutes off the field with a suspected broken nose.
"We thought we played well and dominated in the first half and had we have scored near half-time, perhaps the game might have opened up," Gatland said.
"But for me, it was about winning the game and the courage we showed was outstanding. It just shows the character of this squad."
Two Ben Volavola penalties kept Fiji in touch, at the interval, and when Vereniki Goneva crossed for a try that Volavola converted, eight minutes after the break, Fiji sensed an opportunity to strike.
Thankfully for Wales, the unshakeable Biggar added two more penalties in the second half and despite a late flurry from Fiji, Gatland was left to enjoy a victory that could seal qualification should Australia beat England at Twickenham on Saturday.
For Fiji, they leave Wales with plenty of memories but, with one match left, still pointless. Fiji are also the first country to be officially eliminated from RWC 2015.
"Congratulations to Wales, but I'm extremely proud of our team," coach John McKee said. "Having put in that much effort and hard work and to come away with nothing is frustrating.
"It's very frustrating to be at this stage of the competition with no points on the board. We knew what a tough group it was going to be, but we had high hopes.
"However, it's a credit to everyone involved that we have done as well as we have."
Wales can sit back and enjoy Saturday's game at Twickenham, although Gatland would not reveal where his allegiance would lie. He said: "They (Australia) could do us a big favour by winning, but I'm a Kiwi so I'm not going to be jumping up and cheering for the Aussies am I?"