Rooney -- 18-year-old Wayne -- blasted England into the last eight with four goals and an all-round forward display that has had the some of the world's top coaches drooling and some of the best defenders trembling.
Ronaldo -- 19-year-old Cristiano -- has been instrumental in lifting Portugal from the despair of their opening game defeat as his incomparable skill and sheer zest for the game has helped spark a belief that has swept across the host nation.
The two youngsters will be at the centre of attention on what should be a wonderful occasion at the Luz Stadium but there is so much more to savour in this intriguing clash.
Both teams are buzzing, riding the crest of a wave after recovering spectacularly from losing starts.
Two days into the tournament it was gloom and doom after the host nation fluffed their lines by losing 2-1 to Greece and England threw away a 1-0 lead in the last three minutes to go down by the same score to champions France.
NERVY WIN
Both sides then followed the same winning route to recovery. Portugal got back on track with a nervy 2-0 victory over Russia, England doing the same with a more comfortable 3-0 success over Switzerland.
Portugal then sparked national celebrations by beating Spain for the first time in 23 years, their 1-0 victory catapulting them to the top of Group A.
England followed suit with their best tournament performance since beating the Netherlands 4-1 at Wembley in Euro 96, their 4-2 comeback win over Croatia sparking wild scenes at home and in Lisbon, taken over for the night by the legion of St George.
The party will continue in the capital on Thursday, but only for one set of supporters.
Portugal go into the game with real confidence now, their first competitive win over their neighbours convincing them there is nobody in the tournament to fear.
As so often is the case, what seemed the first choice
Ronaldo started the first two games on the bench but the winger must now be the first name on the team sheet.
England's fullbacks Ashley Cole and Ronaldo's Manchester United team mate Gary Neville will have to be at the absolute top of their game to keep Ronaldo at bay.
Only a suspension has saved the disappointing Pauleta from being dropped and starting in his place up front should be Nuno Gomes, who came on for him at halftime against Spain and scored the winner.
Similarly, Deco will keep the midfield berth he inherited from Rui Costa.
IMPRESSIVE MIDFIELD
England should start with the same 11 who began against Switzerland and Croatia, the development in their side being a matter of tactics rather than personnel.
Manager Sven-Goran Eriksson began the tournament preaching a midfield diamond but the players persuaded him to revert to a flat four, a formation they are all more comfortable with.
The result has been impressive. Steven Gerrard and Frank Lampard have suddenly gelled into a formidable central duo, both strong in the tackle, great passers and full of energy.
Paul Scholes will be hugely boosted by his first international goal in three years, which brought England level against Croatia, while David Beckham is due a captain's performance wide on the right.
Then there is Rooney, carrying a nation's hopes on his broad shoulders -- with the world watching.
Probable teams:
Portugal (4-4-2) - 1-Ricardo; 13-Miguel, 16-Ricardo Carvalho, 4-Jorge Andrade, 14-Nuno Valente; 6-Costinha, 18-Maniche (or 8-Armando Petit), 7-Luis Figo, 20-Deco; 17-Cristiano Ronaldo, 21-Nuno Gomes.
England (4-4-2) - 1-David James; 2-Gary Neville, 5-John Terry, 6-Sol Campbell, 3-Ashley Cole; 7-David Beckham, 11-Frank Lampard, 4-Steven Gerrard, 8-Paul Scholes; 9-Wayne Rooney, 10-Michael Owen.