Nick Robinson's late drop-goal denied Fiji a famous win in Cardiff as Wales escaped by the skin of their teeth.
Fiji kept Wales scoreless before the break and led thanks to a superb 60-metre breakaway try from second row Ifereimi Rawaqa.
Seremaia Bai stretched Fiji's lead with a drop-goal, but lock Isoa Domolailai's sin-binning proved a turning point.
Wales skipper Michael Owen scored a pushover try from a scrum, before Robinson's boot completed the rescue.
Mike Ruddock had asked a largely second-string Wales side to lay claim to a permanent spot following last week's 41-3 loss to New Zealand.
But the Wales coach will have few selection dilemmas after this performance, with only Llanelli Scarlets duo Matthew Watkins and Lee Byrne acquitting themselves well.
Adding to Ruddock's problems were injuries to flanker Dafydd Jones, lock Brent Cockbain, prop Chris Horsman and wing Kevin Morgan which makes them all doubtful to face South Africa next week.
Fiji started with their usual determination to run the opposition ragged and a series of dashes stretched Wales to earn two early kickable penalties.
"We showed determination and a will to win you need when things aren't going your way"
Unfortunately for the visitors centre Julian Vulakoro was just short with his first effort, then shaved the left-hand post with his second.
Robinson also missed his first effort for Wales, after Fiji wing Sireli Bobo was harshly penalised for a whole-hearted tackle on Watkins, then scuffed his second.
In all there were 10 penalties conceded within a scrappy first quarter-hour, with handling errors following a close second.
What few scoring chances there were continued to be spurned, Vulakoro fluffing his third kick before Martyn Williams knocked-on a low pass when Wales at last had the try line at their mercy.
Amongst the mess Dafydd Jones, just returned from injury, suffered a blow to his ankle and the blind-side flanker was replaced by Alix Popham.
Then Wales lock Cockbain, a summer tourist with the Lions, hyper-extended his knee and was stretchered off.
Finally, just before half-time, came a try that was worth the wait when Fiji skipper Mosese Rauluni broke from his own 22.
A great interchange of passes found Rawaqa bursting through midfield, showing exceptional pace for a lock to run it under the posts from halfway.
Vulakoro could hardly miss that kick and slotted the conversion to hand Fiji a 7-0 lead at the break.
Wales huffed and puffed after the restart but, one fine break by Kevin Morgan aside, did not come close to threatening the try line.
Fiji were sniffing a famous upset as the clock ticked down into the final half-hour, especially after fly-half Bai clipped over a drop-goal to put the South Sea islanders two scores clear.
Byrne had a try disallowed by Scottish referee Rob Dickson for a forward pass, but Robinson finally got Wales on the scoreboard with a penalty.
That spurred on the men in red and the pressure saw Fiji lock Domolailai sin-binned as he tried to stop Wales recycling quick ball.
Wales went for the jugular with a five-metre scrum and easily shunted the remaining seven Fiji forwards backwards over the line, Owen touching down.
Robinson should have levelled the scores, but let nerves get the better of him and missed the simple conversion.
Yet the Cardiff Blues fly-half made amends with four minutes left, sitting back in the pocket to give Wales the lead for the first time with a drop-goal.
That proved just enough, as Fiji were left still searching for a Test win over Wales after six attempts.
Wales: L Byrne (Scarlets); K Morgan (Dragons), M Watkins (Scarlets), S Parker (Ospreys), S Williams (Ospreys); N Robinson (Blues), G Cooper (Dragons); J Yapp (Blues), R Thomas (Blues), C Horsman (Worcester), B Cockbain (Ospreys), L Charteris (Dragons), D Jones (Scarlets), M Williams (Blues), M Owen (Dragons, capt).
Replacements: H Bennett (Ospreys), A Jones (Ospreys), R Sidoli (Blues), A Popham (Scarlets), R Sowden-Taylor (Blues), M Phillips (Blues), C Sweeney (Dragons).
Fiji: N Ligairi (Secom, Japan); M Luveitasau (Naitasiri), E Ruivadra (World, Japan), J Vulakoro (Suva), S Bobo (Biarritz); S Bai (Secom), M Rauluni (Saracens, capt); J Bale (Suva), S Koto (Ovalau), A Nagi (Lautoka), I Rawaqa (World, Japan), I Domolailai (Northland), A Doviverata (Yamaha), A Ratuva (Agen), S Koyamaibole (Taranaki).
Replacements: V Gadolo (Suva), T Matawalu (Nadroga), K Leawere (Nadroga), K Salabogi (Nadroga), M Volavola (Nadroga), A Vata (Ovalau), K Ratuvou (Tailevu).
Referee: Rob Dickson (SRU).