Spurs will defend a 3-0 lead from the first-leg of their Champions League round 16 tie.
Davies said, "We can't afford to be complacent, we have to go out there and play our normal game. Especially in the first half, we can't afford to let anything get past us.
“We have to make sure we put on a very professional performance, we can't be complacent, we have to be switched on from the off.
“It would be unbelievable (to reach the quarter finals). Nobody thought we would get this far after our first three games in the group stage.
“It's a massive opportunity for us now. If we can get it done who knows what can happen next? We'll hopefully get this over the line and we'll continue trying to put our best foot forward. Anything can happen."