The Serie A leaders are 3-0 up from the first leg in Glasgow and odds-on to reach the last eight of the competition for the first time since 2006 but Conte has warned against complacency.
"Nobody wants to minimise the importance of this game; qualification is obtained over 180 minutes," he said.
"We've only played 90 and we have another 90, plus maybe extra-time and penalties, against a strong, proud team who will want to make amends for the first leg.
"There is a quarter-final to be reached so we definitely won't under-estimate this game.
"It's going to be a test for everybody, starting with me, then the players and the club.
"Certainly the first leg has given us a seriously good chance of reaching the next round, but in football there are always surprises if you don't play with the right determination and concentration.
"Celtic are a very physical side and can create lots of problems from set-pieces.
"We've got to be fully focused because we want to go through and so we've got to give it everything."