Second-half goals from Carlos Bacca and Denis Suarez saw Sevilla claim the opening leg 2-1 at home last week, putting the Spaniards one step closer to back-to-back titles.
Sevilla can secure a semi-final berth if they avoid defeat in the return leg but Emery said he will not be sending his players out against Zenit with a defensive mindset.
"You always want to win, without considering what the score was in the first leg," Emery told reporters. "We could reach the first goal but not the second one.
"We know this is a 180-minute tie and we are ready to play extra time or penalties if we have to.
"Zenit knows to compete very well, they have a lot of experience and all their players are internationals. They have won a Europa League recently and their coach has experience and has also won a Europa League title himself.
"We are gonna try to compete, assess how the game is going during the 90 minutes and think about our advantage. We will try to win in Zenit's stadium, but we are well aware how difficult that will be."
Sevilla have won the UEFA Cup/Europa League three times since 2006, and winning a record fourth title would be a massive moment in the club's history.
"The Europa League is something very special for Sevilla," Emery added. "We won the competition last season and two more titles not that long ago.
"Our fans really like this tournament, they have big hopes with the team this year and for us, tomorrow's game is unique and something which can bring us to another important moment in the history of Sevilla."
