Dias’ Portugal currently top Group F after their 3-0 triumph over Hungary on Matchday One, and victory over Germany would guarantee their place in the knockout stages.
But Die Mannschaft will be desperate for the win themselves as they look to keep their qualification hopes alive and put an opening defeat to France behind them.
All friendships will be forgotten once the match gets under way as Dias and Gundogan focus on performing for their respective home nations, but the Portuguese defender admitted they’d still taken the time out to wish each other well.
“As it happens I did talk to (Ilkay) Gundogan,” Dias declared in a pre-match press conference.
"It wasn’t anything philosophical, I just wanted to wish him good luck and he did the same.
“On the pitch there will be two very strong sides, two of the best in these Euros and also two teams who want to have possession and dominate the game.
“We know Germany very well, we know what they’re capable of, we know the players they have, but we also have our weapons.
“More than the individual abilities of each team, the one who wins will be the one who deals with the collective issues better and the one that’s better prepared form a collective standpoint.”
Coming off the back of a phenomenal debut season at City, where Dias picked up three separate individual awards, the defender’s confidence is sky high.
The 24-year-old featured 50 times in a City shirt across the 2020/21 campaign and, despite the clustered fixture calendar, he insists that his first campaign in English football has provided the perfect preparation for the rigours of tournament football.
He reflected: “The only thing I can say is that the mentality is the same, we want to win every single match, we want to be better than the opponent and we want to win.
“Individually, that helps me a lot… every game prepared me for the Euros.
“It was a very tiring season but I’m always a very focused player and focused on the individual elements, on the physical aspects for instance.
“Little by little, I became prepared and I am ready to be at the highest level.
“In order to win the Euros, we have to be at the highest level."
If recent history is anything to go by, then the omens don't look good for A Selecao.
Portugal have failed to beat Germany in over 20 years since current Porto manager, Sergio Conceicao, grabbed a hat-trick in a 3-0 Group Stage win at Euro 2000.
Dias is confident they can end that run when they lock horns in Munich, but is also under no illusions about the magnitude of the task they have on their hands to break the curse.
“Our expectations are that we’re going to be facing an amazing team, one of the best in this Euros,” he explained.
“We’re also one of the best to be sure and we’re fully aware that even if we start not the right foot, we need to have our feet firmly on the ground.
“We have to be better than them and better than we were (against Hungary) in order to win this match.”
Portugal v Germany kicks off at 20:00pm (UK) at Bayern Munich’s Allianz Arena.
You can find an in-depth report on proceedings soon after the final whistle on mancity.com and our official app.