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 favour in the 10th minute when he spilled the ball five metres out from his own line and Wales got across the stripe through Dalton Grant but scramble defence by Amone and Tesi Niu denied him.
Come the 16th minute and the Welsh had their try through winger Kyle Evans, who forced an error from Siosifa Talakai with a strong tackle and then took a pass from Ralph to race away and score. Matty Fozard converted for 6-0.
Tonga needed just five minutes to hit back when Daniel Tupou took a pass from Niu to cross in the left hand corner for the first of his three tries.
A dropped ball by Connor Davies late in the first half proved costly for Wales, with David Fifita powering across from close range to give Tonga the lead for the first time.
Keaon Koloamatangi's second try of the tournament on the stroke of half-time extended Tonga's advantage to 16-6 at the break as Kristian Woolf's side started to hit their straps.
Fullback Tesi Niu was next to score for Tonga, evading several defenders on a weaving run to the line in the 47th minute to make it 22-6.
Some desperate online defence by Wales lock Joe Burke denied Lolohea a try in the 51st minute but weight of possession eventually told when Tupou crossed for his second four-pointer on the hour mark and the floodgates threatened to open.
Manly flyer Tolutau Koula produced a spectacular play in the 66th minute when he launched himself across the sideline and flicked the ball back inside to set up a try but the video referee correctly ruled the ball had grazed the line before he scooped it back.
Some slick passing on the left edge by Tonga finished with Tupou completing his triple after taking the final pass from Talakai, who converted the try for a 32-6 lead.
Tupou got across the line again with three minutes to play but an obstruction by Talakai in the lead-up meant the veteran flyer would have to settle for a hat-trick.
Greatest tries that never were: Tonga edition
Match Snapshot
- Kasey Badger became the first female to referee a men's World Cup match.
- This was the first ever match between Tonga and Wales.
- The last time Wales beat a team from the Southern Hemisphere was the 2000 World Cup quarter-finals when they beat Papua New Guinea 22-8.
- Wales had 22 tackle breaks in the opening half compared to 15 for Tonga.
- Tonga conceded five penalties in the first half, Wales just one.
- Wales lost their captain's challenge in the 36th minute when they lodged an unsuccessful challenge against a Connor Davies knock on.
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- Tonga completed 29 of 41 sets at 70 per cent. Wales completed at 74 per cent (23 of 31).
- Wales were forced to make 389 tackles compared to Tonga's 256 tackles.
- Roosters star Daniel Tupou now has nine tries in 14 Test matches for Tonga.
- Cowboys superstar Jason Taumalolo is free to resume for Tonga in their final Pool game against Cook Islands having served his three-game ban stemming from the NRL Preliminary Final against Parramatta.
Tupou the hat-trick hero
Plays of the Game
Kyle Evans had a sensational debut for Wales, refusing to be overawed by the sight of Tongan powerhouse Siosifa Talakai bearing down on him. The Wakefield Trinity winger put a couple of massive hits on Talakai, the first resulting in a spilled ball which Wales scooped up and Evans raced away for the game's opening try. Early in the second half with Tonga cranking up the pressure Evans stopped Talakai in his tracks on the left edge and again the ball came free.
What They Said
"It was a tough game tonight, Wales played outstanding. They started well and we just gave them too much ball and they utilised it. We wanted to start well, start strong and fast, but we didn't respect the ball in the first half and that led to their first try. We know what we need to fix, just our own individual errors. I'm extremely humbled and grafeful [to get three tries]. The boys did all the hard work on the inside." - Tonga winger and player of the match Daniel Tupou
Woolf: 'We are building'
"You have to take your hat off to our boys, they're all heart. They commit totally against a big, physical team and again I'm proud of them. We've lost but they gave everything and their resilience is tremendous. Kyle Evans can feel very, very proud of his debut for Wales rugby league. The try he scored was great and some of his defensive work was great as well, forcing errors." - Wales coach John Kear
"Union is my background but I've always wanted to play league and certain people have given me opportunities which I'm very grateful for which led me here. I just get stuck in, that's the main thing. This is one night I will always remember, it's a dream come true for me." - Wales winger Kyle Evans
What's Next
Tonga face Cook Islands on October 31 in their final hit-out before heading into the quarter-finals, where they are set to face Samoa.
Wales will look to secure their first win of the tournament when they face the Kumuls in the last of the Pool matches in Doncaster.