The Real Madrid attacker has branded the win "important", but the 21-year-old has now switched his attention to Tuesday's clash with Portugal Under-21s, who beat Serbia Under-21s in their first match of the competition.
"Football is about scoring goals, but this game is finished and now we have to be focused on Portugal," Asensio told UEFA.com.
"I scored three goals and I helped my team. I'm very happy with this win. The win is important, but also the number of goals. We scored five and that's important if we want to reach the semi-finals."
Spain Under-21s are four-time winners of the competition, but they failed to make it to the 2015 finals after losing out in the qualification playoffs.