Super-sub Borriello secured a 2-1 result against Cluj with a sensational left-foot volley from a tight angle.
"More than anything else, it was an important goal, as it allowed us to earn our first three points in an exceptional competition like the Champions League," said the striker.
"It was a tougher game than expected, but we had our chances. We ran a few risks at the back, but brought home the points.
"Now we must try to improve those things that didn't work this evening."
"We cannot say anything yet. We'll only be in the clear if we continue to play with this level of tenacity," added Borriello.