Betis came from a goal down to win 2-1 on the night.
Adrian said afterwards: "This is what this beautiful sport has in store for us. Sometimes, defeats hurt a lot, but they teach us a lot. Today's victory... It was huge. I have no words to explain it.
"The team, for days, had been incredibly motivated, with 31,500 people coming to training. Every Betis fan in the world deserves this victory.
"We had everything under control. They scored a goal against us with the first chance they had. Their tactic tonight was to defend deep and counterattack. They have good players. We were clear winners. We had clear chances, despite the score against us, but the team has a winning gene acquired this season.
"We've learned from painful defeats. This team fights for everything. We're in a very good situation. We have to enjoy it and keep going because this doesn't end tonight."
This was Adrian's first Derbi in over 12 years and he added: "I was really looking forward to it and excited. I've played in other derbies before, but I haven't won with the first team. We want more, to finish the season as well as possible and achieve great things with this badge."