The Tottenham midfielder remains optimistic regarding the future of his young team-mates despite their disappointing results in Israel
Germany suffered a 3-2 opening defeat to Netherlands prior to their 1-0 loss to reigning champions Spain, which leaves them unable to qualify for the semi-finals with one game remaining.
Although he admits he is disappointed to be heading home early, Holtby insists the future is bright for his national team.
"It’s very difficult to accept that we are out of the tournament. We could just as well be sitting here with two points under our belt,” he told UEFA.com.
“It was still a great experience for everyone. I am convinced that a lot of players in this Under-21 team will become world-class footballers in the future."
Germany face Russia in their final group game before departing Israel, and Holtby insists his side are fully focused on salvaging some pride before concentrating on their respective club pre-seasons.
“We grew together as a team, so there is quite a bit of sadness that we have our final match in just two days," he continued.
“I am not thinking about any other things like holidays or the next pre-season with Tottenham. Against Russia it's time to prove we deserve to be in this tournament.”
Centre-back Stefan Thesker, who was a late call-up to the party heading to Israel, insists he has learned some valuable lessons from the championship despite poor results.
“I joined this team quite late during the qualifying campaign and didn’t have a lot of experience at this level. That’s why I was able to take two or three steps in the right direction at this tournament. I will put this down as a good experience, even if it wasn’t a success,” Thesker explained.