The headlines will be dominated by Cristiano Ronaldo and Gareth Bale but this game is about more than two Galacticos going head-to-head for a place in the Euro 2016 final.
Paddy Power are taking the match odds and vastly increasing them for anyone who is yet to open an account. New players can take 7/1 (8.0) about Portugal or a massive 14/1 (15.0) on Wales to win the match.
Cristiano Ronaldo may not have been at his sparkling best but if the three-time Ballon d'Or winner is able to reproduce the kind of performance that he put in against Hungary, then a Welsh backline missing Ben Davies may struggle to contain the 31-year-old forward.
Chris Coleman's men were 80/1 (81.0) outsiders pre-tournament, but their progression throughout the competition has shown that they are more than just also-rans; they're legitimate contenders on the international stage.
While the 29/10 (3.90) will be without the services of Davies and Aaron Ramsey, their formation is unlikely to change, meaning James Collins and Jonny Williams or Andy King should be able to slot straight into the side without too much disruption.
Even if they struggle to contain the attacking talents of Ronaldo and Nani, Coleman's side showed in their 3-1 win over Belgium that they have plenty of firepower in reserve, even without Bale getting on the scoresheet.
Given that Portugal have flattered to deceive in several games this season, those who believe they are set to struggle once again will surely be tempted by the 14/1 (15.0) quotes for new Paddy Power customers.