The Spanish outfit finished bottom of their section with just one point after losing five of their six games in the competition.
"We promised before the match that we'd give all we had to produce goals and a win for this support of ours who deserve more than we've given them this Champions League," Pardo told reporters at a press conference.
"We didn't manage that but we did show the desire and the hard work. We have suffered a bit of bad luck with our results in Group A. We've played with seriousness and intensity because we were so full of pride and ambition.
"For any player this is the competition to be in. From my point of view it has been an early experience because I'm still young."
"I'll benefit from this. Now it's back to the league where we have to concentrate on each game so that we finish as high as possible and go as far as we can in the cup."
Sociedad's campaign ended with a 1-0 defeat to Bayer Leverkusen on Tuesday.