Midfielder Adam Gnezda Cerin says Slovenia are not satisfied with reaching the last 16 at Euro 2024 as they prepare to face Portugal on Monday.
A goalless draw against England in their final Group C fixture helped Slovenia advance as one of the four best third-placed teams.
It is the first time they have reached the knockout phase of a major competition.
“It is a new milestone for the Slovenian national team, for Slovenia in general,” said Gnezda Cerin.
“We have our goals and I think tomorrow’s match will be a beautiful evening for everyone to enjoy because these matches are something you dream about as a kid who starts playing football.
“We are not done. We will try to play tomorrow’s match at the highest possible level.”
Slovenia, appearing at only their second European Championship, drew their three group matches.
“We are prepared for Portugal,” said Gnezda Cerin, who plays for Panathinaikos.
“They’re a very, very talented team and they can cause you problems all around the pitch.”
Portugal won Group F despite losing 2-0 to Georgia in their final group game.
They have reached at least the quarter-finals in five of their past six European Championships, including winning the tournament in 2016.
Slovenia won 2-0 when the sides met in a friendly in March, ending a run of 11 Portugal victories in a row.
Midfielder Bruno Fernandes said that defeat has put Portugal “on their toes” for the game in Frankfurt at 20:00 BST.
“We don’t have a lot of time to think about what was. We have to think about what’s going to be,” Manchester United’s Fernandes said.
“We respect every opponent. This [Slovenia] team has very relevant names, and high-quality players – we respect them greatly.
“After the negative results, people tend to focus on the negative aspects, but this is how football works.”