Spurs put one foot in the Europa League quarter-finals when they opened up a three-goal lead against Inter Milan last week.
But keeper Friedel reckons they need a goal to be certain of victory in tomorrow's return leg.
He said: "They are still in the match at 3-0 but we'll go out there with the attitude to score.
"And if we get that decisive away goal, they'll have a mountain to climb.
"Away goals are so important and getting a clean sheet is too, as was the third goal before going to the San Siro.
"Before the game we'd have taken 3-0 so we were very pleased - but it's only halfway in the tie."