The goalkeeper is part of the Spanish squad alongside fellow goalkeepers Ruben Blanco (Celta Vigo) and Kepa Arrizabalaga (Athletic Bilbao).
Spain kick-off in Group B against Macedonia on Saturday followed by Portugal on Tuesday and the final group match against Serbia on Friday.
There are three groups of four as the finals are extended from eight to 12 teams. However, only group winners will progress to the semi-final with the best runner-up in the three groups making up the last four.
Spain have an outstanding recent record in the UEFA U21 Finals - winners in 2011 and 2013 - and they qualified impressively again with just one defeat in 10. However, the strength of some of the countries at this level is underlined by the fact that that wasn't enough to win their qualifying group. Instead, 2015 winners and reigning champions Sweden won the group unbeaten as they defend their trophy.
Pau said: "We have a very good national team, we have very good players but I think the other teams have very good players as well. It’s going to be difficult but we have a chance to arrive in the final.
"If we can play how we played the last two games (play-off qualification against Austria) maybe we will have a chance to fight to arrive in the final and to win.
"I’m very happy, I’ve been playing in the last two years to qualify and for me it’s a pleasure to be with the squad, to be with my mates and I hope we can have a good performance.
"We're playing with the best European players in our age group so I think it’s a very good tournament to show your level and to get experience."
England, meanwhile, are in Group A and up against hosts Poland, holders Sweden and Slovakia.
Czech Republic, Denmark, Germany and Italy are in Group C.