The Magpies will have to overturn a two-goal deficit in the second leg of their quarter-final tie, having lost 3-1 at Estadio da Luz.
The defender told the club's website: "The away goal's massive. We said that at the start of the game, if we were going to do anything, we had to take an away goal back to St. James' and if we play like that at St. James' and we don't concede the soft goals we conceded, you never know.
"They'll come to our place and they'll expect our fans to be right on them like their fans were [yesterday].
"We've got to take the positives from [yesterday] and if we play like we did in patches tonight at home, and don't concede the soft goals, anything can happen."
The second leg takes place at St James' Park next Thursday.