Perez was quick to praise the battling spirit shown by his teammates to grab the late goal that ensured their progress to the semi-finals.
"We played a great game," UEFA.com quotes Perez as saying. "We knew Newcastle had great players, and we've knocked out a great team.
"In the second half it was obvious that Newcastle were going to push forward a little more, and we were pleased to have the extra breathing space that the two-goal lead gave us. Fortunately we managed a positive result.
"I think we showed efficiency and great character, and a great attitude. Sometimes you have to play, sometimes you have to battle."
Chelsea, Basel and Fenerbahce are the other teams in the semi-finals.