England reached the last four of the World Cup for the first time since Italia ’90 on Saturday after goals from Harry Maguire and Dele Alli secured a 2-0 victory over Sweden.
Gareth Southgate’s side will now face Croatia, who knocked out hosts Russia on penalties, in the semi-finals in Moscow’s Luzhniki Stadium on Wednesday.
Croatia are led by Real Madrid midfielder Modric and, while Dier is aware of their quality, he believes England are capable of further improvement in the tournament.
“He is a fantastic player and it is a very good team,” Dier, who scored the winning penalty in the last-16 shootout victory over Colombia, said in Samara’s Cosmos Arena. “Croatia have a lot of fantastic players.
“We are very happy that we won it, but there’s a big prize ahead after every game and this one was no different, so we have to focus on the next game. We focus again, we can’t lose that.
“That’s been the mentality until now, just to go one game at a time and hopefully that can continue. It means everything to create our own history. We keep doing that game after game. We keep going and aim to try and get as far as we can.
“I think that we have developed very well, but we have shown a good level from the beginning. We showed a good attitude with commitment and fight from the beginning. Obviously, a team’s quality can always improve and we will try to keep improving.
“I think we believe that we can improve a lot, but we will try to do that. I think we have had the right attitude and mentality and willingness to fight from the beginning.”
However, there could be more fans at England’s semi-final, with a place in the World Cup final against France or Belgium at stake, and with Moscow an easier destination to reach from the United Kingdom.
Dier has invited more fans to join the travelling support of the Three Lions, as they aim to emulate the World Cup-winning heroics of the 1966 team.
“I can only recommend for England fans to come,” Dier continued. "It has been fantastic so far. The tournament and the organisation and everything about it has been great.
“I am sure the England fans here have seen that, I hope the England fans back home will see the same thing.”