Glenn says the team have to be totally ruthless in the encounter with Sunderland at the Lane on Saturday.
The Wearsiders are sitting bottom of the Premiership following three successive league defeats, but were lifted by a victory on penalties over Blackburn in the FA Cup on Wednesday.
The boss is taking nothing for granted and insists the team must be prepared to scrap for the spoils if neccessary.
"We've got to go into this game and be totally ruthless - not with Sunderland, with ourselves," said Glenn. "On paper, and the game is never played on paper, we are at home and we should win.
"That doesn't happen in football, you've got to go out there and earn the right to win the three points in every game.
"We've got to have the right mentality - against Sunderland and then against Fulham to get the points. If it is a scrappy affair then so be it.
"We'd like to play wonderful football and win the game, but teams are fighting for survival and we might be forced into an awkward game. We've got to overcome that and be ruthless and demanding of ourselves.
"In many ways, coming to White Hart Lane might be a bit of a release for them and we've got to be wary of that."