And England striker Defoe believes he can keep banging the goals in for Pompey, provided they don't take their foot off the gas against the little-known Portuguese side.
He said: "Vitoria finished third in their domestic league so it's going to be a tough test.
"I'm really looking forward to travelling to play some of the best sides in Europe but we've just got to take it one game at a time and keep working hard as a team.
"I'm always going to get chances because I'm playing alongside quality players. When I do get the chances, I've got to take them.
"If I'm playing games and feeling sharp, then I'll score goals.
"I want to improve with every game and I just work hard and try to get my goals."