Serie A leaders Napoli made their first appearance in the last eight of Europe's elite club competition when they visited Milan on Wednesday, losing 1-0 to an Ismael Bennacer (25) goal.
"There are zero risks around this match. The only risk is achieving infinite joy because we’ve never reached this level and if we win we go even further," Spalletti told reporters on Monday.
"I will only be happy tomorrow if we get through to the next round, otherwise any great performance will be scant consolation," he added.
"We need to play the way we did in the first leg when we emerged with a slight disadvantage but no real remorse. In general, that performance is what I expect."
The match will see the return of striker Victor Osimhen (24), who missed both of Napoli's earlier defeats to Milan this season.
The Nigeria international, Serie A's top scorer with 21 goals, was back on the pitch for 17 minutes in the goalless home draw against Hellas Verona on Saturday after a thigh strain.
"Milan play modern, attacking football with a high press, they thoroughly deserved to win the Scudetto last season and will come here to take the initiative. Having Osimhen to deal with will cause them worries too," Spalletti said.
Napoli will be without centre back Kim Min-Jae (26) and midfielder Andre Frank Zambo Anguissa (27), who are suspended, and Giovanni Simeone (27), who has a thigh injury, although Spalletti said there was sufficient depth in the squad to replace them.
"We have a squad that allowed us to reach this stage, not just 11 players. Getting the right exercise in training is crucial too, otherwise, you forget the movements and get out of practice, so they all contribute there too," he added.
