Juve meet Lyon for the second-leg of their round 16 tie needing to overturn a 1-0 deficit.
Sarri said, “We need a great performance, certainly. Lyon have evolved and become far more solid since moving to three at the back, playing with density in midfield and also pace on the counter.
“With the first leg result too, it's a very tough game we need to approach with calm and focus.
“Unfortunately, losing the first leg means we are forced to play a game that most suits their approach to the counter-attack. Memphis Depay is an important player to get back, so it's very difficult, but still entirely possible.
“It's impossible to play without pressure tomorrow, so what we need is sharpness, which is slightly different. We played the first leg with a crowd, the second behind closed doors, but these are the conditions we all have to deal with. It's always a little sad to play without a crowd, but even more so in the Champions League, the best club competition in the world.
“We can only hope this won't last too long, as it is also difficult for the players to always be without fans."