Last weekend's nailbiting 28-25 victory over hosts England at Twickenham sent Welsh hopes soaring in spite of a crippling injury list, and the mood was buoyant as thousands of fans formed a red tide pouring into Cardiff for the afternoon kickoff against Fiji.
The euphoria of beating old rivals England has coursed through the Welsh valleys all week. But with the start approaching and bars around the stadium packed to the rafters, there was also a nervous tension over what awaits in the Pool A game under the stadium's closed roof.
"This is a do or die game," said fan Mark Bowen, part of large group wearing Wales shirts, face paint and fluffy sheep hats. "We dare not mess it up now."
Welsh rugby convert Otto Arnold, from Corboba in Argentina, described Cardiff on match day as "the capital of rugby".
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Fiji are not just here for souvenirs, though, and showed in defeats against England and Australia that they have the potential to gatecrash the Welsh party.
Wales need only cast their minds back to a 38-34 defeat at the 2007 World Cup for a sobering reminder of the damage the powerful Pacific Islanders can do.
The Welsh gained revenge four years later with a 66-0 stroll but struggled in a 17-13 win last November against a side playing nearly half an hour with 14 men.
The momentum gained from beating Uruguay, then England, should carry Wales through, but every tackle will cause a collective wince from the sell-out crowd as Wales can ill-afford any more casualties.
Centre Scott Williams and winger Hallam Amos both suffered tournament-ending injuries against England, joining the likes of fullback Leigh Halfpenny on the list of players unavailable to coach Warren Gatland.
Matthew and Tyler Morgan have been brought into the backline, replacing fullback Liam Williams and centre Scott Williams, while Alex Cuthbert replaces Amos on the wing.
While Wales have a patched-up look and have had precious little recovery time from the brutal Twickenham contest, they can at least breathe a little easier in the knowledge that they will not have to face two of Fiji's best players. Destructive winger Nemani Nadolo misses the game after being handed a one-match ban and scrumhalf Nikola Matawalu was ruled out by injury.
Thursday's 74,000 crowd will push the tournament's total attendance through the one million mark.
(Editing by David Goodman)
