The Young Lions struggled to find their feet during the group stage, but a 3-1 win over Spain in the quarter-finals showed their true potential.
Goals from James McAtee, Harvey Elliott and Elliot Anderson saw them home on Saturday, and Carsley wants more of the same from a side that he feels are just getting into their stride.
Speaking to reporters at the National Football Stadium in the Slovak capital, the manager said: "I spoke about the longer we can stay in the tournament, the more fluid the players will become.
"We've been together now 22 days, so when you think about that from a club point of view, if this were a club team, we're almost just past that pre-season level now and start looking at the first and second game of the season."
He continued: "The Spain game was an accumulation of team spirit and togetherness."
They face a Netherlands side that defended outstandingly against Portugal on Saturday, winning 1-0 despite being down to 10 men for the majority of the contest.
The Dutch will have three players suspended for the semi-final - midfielder Kenneth Taylor, captain Devyne Rensch and winger Ruben van Bommel - whilst England will be without Tyler Morton, who picked up his second yellow card of the tournament against Spain.
Despite the differences in personnel, Carsley is expecting another hard-fought encounter.
He added: "The Netherlands are a team that we've been watching now for a while. They're very attacking, very expansive in the way they play, technically very good. I really like the system that they play as well. Very similar to the Spanish. We expect a really tough game and we're fully prepared for it."
It is expected to be 32°C for the 18:00 CET kick-off in Bratislava. It has been warm in Slovakia for much of the tournament, and despite the players struggling to adapt in the 0-0 draw against Slovenia during the group phase in Nitra, the manager believes his charges won't make any excuses for the oppressive heat.
The 51-year-old explained: "We've been quite fortunate since we've been here that it's been very hot.
"We've trained at some of the hottest periods of the day, not on purpose, but just the way that it's worked out with our training time. We've not shied away from the heat. We've exposed the players to it fully.
"We're ready for it. We're fully prepared now. We've been here long enough now to acclimatise to the heat. We've definitely got hydration strategies in place in terms of what the players need to cool down quickly and hydrate quickly.
"I think our use of the substitutions has been effective in terms of our timings. We've probably gone a little bit earlier than you would in normal circumstances, based on how hot it's been... Everyone's capable and ready to play, which has been a massive benefit for us."