Lucas Torro and Ante Budimir struck the goals in San Sebastian on Sunday.
Moreno said afterwards: "Everything went perfectly. When it came to giving up the ball, they could have hurt you. On a defensive level, we did a great job of covering up their strengths and we know that the line between winning and losing is very fine.
"We have to be very happy with the team's effort and for finding victory on a very difficult pitch. In addition, we were accompanied by a lot of people from Pamplona who I suppose enjoyed it. This victory is for them."
Moreno added: "We were looking for it (an away win), we drew in Valencia and Getafe and we were close. We had to insist on being calm. It came in a difficult stadium, against a difficult team with a great coach. This victory gives us peace of mind even though we already have the Copa del Rey match."