From the moment the draw was made, England's Group B match against Wales was the one both nations were most looking forward to.
The wait will come to an end on Thursday when Chris Coleman's side take on a team Wales talisman Gareth Bale described as "the enemy".
"Obviously there's a lot to it," said Dier, who scored the opening goal in England's 1-1 draw against Russia. "I think as well it might be a bit less of an international game and a bit more of an English game, especially with the players.
"It might be a bit different to all the others games you've seen in the tournament, so I think that's good for the spectators as well.
"Obviously it's a massive game for them and for us, for many different reasons. Everyone is going to look forward to it.
"I think the underdogs are always up for it, always wanting to prove a point and that makes it even harder for the favourites.
"If we are the favourites, we need to be even more well-prepared and more ready for it because they'll be desperate to do their best obviously after the result they had as well."