Will it be the 2019 winners of the 2021 runners-up who book their place at the UEFA Nations League Finals?
Spain came into this international window at the summit of Group A2, but relinquished top spot at the weekend.
La Roja were beaten 2-1 by Switzerland at La Romareda, conceding the decisive go-ahead goal just four minutes after Jordi Alba had lashed home an equaliser.
This is a real surprise given that Spain had only lost two competitive home games since 1991 beforehand, these against England in 2018 and Greece in 2003.
The latter was the last time, prior to the weekend, Spain had played in Zaragoza; they might not be returning for a while.
So, for Luis Enrique’s team to regain top spot in the group, they simply must win this one.
Portugal simultaneously were demolishing Czech Republic 4-0 in Prague on Saturday night.
Diogo Dalot the surprise scorer of a brace, while Bruno Fernandes and Diogo Jota were also on the scoresheet.
Fernando Santos’ side have now won three of their last four Nations League games, the exception a shock 1-0 defeat in Switzerland on matchday four.
A Seleção have also lost just one of nine Nations League matches on home soil, lifting the inaugural trophy at Estádio do Dragão three years ago.
So, will Portugal get the point they need against their Iberian neighbours at Estádio Municipal de Braga?