A committed Wales outfit pushed Tonga to the limit before the hot favourites prevailed 32-6 at Totally Wicked Stadium in St Helens.
The win leaves Tonga on track for a blockbuster quarter-final showdown against Samoa but they will need to improve their discipline and get some combinations right if they are to challenge for the title.
An early mistake by halfback Josh Ralph at dummy half put Wales under huge pressure but they held firm for a number of sets after Tui Lolohea and Talatau Amone had forced line dropouts with well placed grubbers.
Tongan winger Sione Katoa returned the...