"We can go into the game against Porto with confidence because we passed a difficult test today," UEFA.com quotes him as saying. "We need to get everyone fit again and hope to be fresh for a match that will be like a final for us.
"It's not easy to play at this tempo every three or four days but we will try to do our best because we really care about the Europa League and we want to go as far as possible.
"We are confident we can still go through after defeat in the first leg."
Benitez will be looking to win the Europa League for the second successive season, after leading Chelsea to victory in last year's final.