Hugo Alvarez, Borja Iglesias and Anastasios Douvikas scored the three goals for Celta.
Giraldez said, "We had a very complete first half, very intelligent, with a lot of physical effort on a brutally hot day. Very happy with the team's image throughout the match, except after 2-1 when we had 20 minutes in which we were more hesitant.
"The team was generous and brave. I liked it. The 2-1 score was not a situation where we defended poorly and we were penalised again by the opponent's first chance. There were moments of doubt, of course.
"Hopefully we can close out games sooner when we are so superior on the pitch. The contribution of the bench has once again imposed itself on us and we had plenty of chances to win the game more comfortably. The result is fair and even short."