Portugal can seal their Nations League last-four spot on Tuesday, if they can avoid defeat against Spain.
Cristiano Ronaldo and Co are currently top of Group A1, two points clear of the Spaniards ahead of their final game before attentions turn to the Qatar World Cup.
On Saturday, Portugal thumped Czech Republic 4-0 in Prague thanks to a brace from Diogo Dalot and a goal from his Manchester United teammate Bruno Fernandes, while Liverpool's Diogo Jota completed the scoring.
"The Czechs have a good team, but we were well prepared for them and executed our game plan perfectly. After the third goal the game was done," said Portugal coach Fernando Santos.
Spain, meanwhile, fell to a shock 2-1 home defeat against Switzerland last time out and go into the match in Braga having not won in Portugal since 2003. The last four matches between the teams have ended in a draw.
“Our goal would be the same even if Spain hadn’t lost, we will try to win the match in Braga,” said defender Dalot. “It’s going to be a complicated match but we will do out best to make it to the next round.”
Forward Joao Felix could return for the Portuguese – who won the inaugural Nations League in 2019 – after missing the Czech Republic victory due to injury.