Lopetegui saw his young Spanish team beat Norway Under-21s 3-0 in their semi-final in Netanya.
Goals from Rodrigo, Isco and substitute Alvaro Morata mean that Spain reach another Under-21 final after winning the last tournament and Lopetegui said the whole team deserved credit.
Speaking to Sky Sports 2HD, Lopetegui said: "We are happy with the performance and of course the result. In the second half Norway played well physically and tactically and we have beaten a good team.
"The second goal by Isco came at the perfect time for us but in the first period the Norway goalkeeper was exceptional. This is how football is though and we have progressed.
"At the moment we are tired, we have good players but we still think that we can improve."
Barcelona midfielder Thiago captained the side and he echoed his manager's thoughts.
He added on Sky Sports 2HD: "I think we played well and we are getting better. We are very comfortable playing the Spanish way.
"It's the semi-final and we were a little tired in the second half but the luck is with us.
"It's a final and because we are there we will be happy to play anyone."