First-half tries from Owen Williams and Ashley Beck gave Wales a scrappy, incohesive 17-7 win over Tonga at the Millennium Stadium in Cardiff.
Friday's showpiece simply spluttered its way through a catalogue of handling errors and set-piece calamities, interspersed with thunderous moments of physicality from Tonga as they kept themselves in the game until the death.
Despite the quality of Leigh Halfpenny, George North and James Hook in the backs, Wales laboured to victory over the Pacific Island side - who showed technical excellence at the breakdown but were too often let down by their handling and tactics when it mattered most.
Tonga had impressed in patches against France last Saturday in Le Havre, but their flashes of indiscipline undermined their efforts. This time there was no nonsense, simply enormous defence from a squad that physically imposed themselves on the right side of the law.
Lloyd Williams came close to a charge-down try after five minutes - had Ryan Jones got a hand on the bouncing ball he might have been in - but both teams fell victim of the choke tackle in a disrupted opening that set the tone.
Viliami Ma'afu's fine tackle on Owen Williams halted another Welsh surge but scrum troubles for Tonga gave Wales a second successive penalty for Hook to boot into the corner to set up field position. It ended in three points off Halfpenny's boot.
Williams then bounced back from Ma'afu's thunderous hit by scoring an excellent try on debut.
The outside centre was released by Leigh Halfpenny in a counter-attack and broke through outstretched Tongan arms to race away for the first try. Consultation from the TMO deemed that Sione Kalamafoni's questionable hit on Hook was not illegal.
A flat first-half wasn't aided in any shape by some painful handling errors from Tongas, with Viliami Helu in particular having a minute to forget with two knock-ons, but Wales did their best to lift the tempo.
Ashley Beck stepped his way to a brilliant finish in the left corner, coming after George North had been released on an inside ball that left Tonga back-pedalling. It put Wales 17-0 up after only 25 minutes and suggested they would score many more, rather than none whatsoever.
Set-piece turmoil meant Tonga had no key to stick in the ignition, Taniela Moa showing sparks but knock-ons again sucked away any momentum.
Everything just needed to click and with enough effort, Tonga made it happen. Ma'afu's powerful carry and offload released Helu on the angle as he shot like an arrow to dive over by the right of the posts.
Hallam Amos was denied a try on his first start for Wales after the break as his heel scraped the touchline, with the hosts only holding out a ten-point lead over their abrasive visitors.
Tonga's forward pack though began to take control - winning consecutive scrums and continuing their good work at the breakdown by winning penalties.
It left the home crowd twitchy under the Millennium Stadium's closed roof - Luke Charteris dropping the ball over the line not doing them any favours - and when the TMO correctly denied Wales for a third time after North burrowed over in the 70th minute it was destined to end as a tussle.
Given the second half finished scoreless, you would have been forgiven for deciding to give it a miss.
Tries: O Williams, Beck,
Cons: Halfpenny 2
Wales: 15 Leigh Halfpenny, 14 George North, 13 Owen Williams, 12 Ashley Beck, 11 Hallam Amos, 10 James Hook, 9 Lloyd Williams, 8 Ryan Jones (c), 7 Justin Tipuric, 6 Andrew Coombs, 5 Ian Evans, 4 Luke Charteris, 3 Rhodri Jones, 2 Ken Owens, 1 Paul James.
Replacements: 16 Emyr Phillips, 17 Ryan Bevington, 18 Samson Lee, 19 Dan Lydiate, 20 Sam Warburton, 21 Rhodri Williams, 22 Rhys Priestland, 23 Jordan Williams.
Tonga: 15 Vunga Lilo, 14 Fetu'u Vainikolo, 13 Siale Piutau, 12 Mata'ali Paea, 11 Viliami Helu, 10 Latiume Fosita, 9 Taniela Moa, 8 Viliami Ma'afu, 7 Nili Latu Langilangi (c), 6 Sione Kalamafoni, 5 Joe Tu'ineau, 4 Lua Lokotui, 3 Sila Puafisi, 2 Vaea Taione, 1 Eddie Aholelei.
Replacements: 16 Suliasi Taufalele, 17 Taione Vea, 18 Tevita Mailau, 19 Hale T Pole, 20 Opeti Fonua, 21 Samisoni Fisilau, 22 Fangatapu 'Apikotoa, 23 David Halaifonua.
Referee: Mike Fraser (New Zealand)
Assistant referees: Craig Joubert (South Africa), Luke Pearce (England)
Television match official: Carlo Damasco (Italy)
Assessor: Clayton Thomas (Wales)
by Ben Coles