Messi has been withdrawn from the squad for the game.
The Romanian coach stressed that a starting line-up without Messi will be more compact in defence although the Argentine can take the team to another level when he starts.
"But his absence will make them play with a better attitude in defence. We want to win tomorrow. For us, victory is very important."
Lucescu went on to stress that the rumours surrounding Messi's future have affected Barcelona who are a new team with a new coach in the dugout and, as a result, need time to gel.
"Barcelona are one of the best teams in the world," Lucescu added. "They are not going through their best moment. The Messi case creates an atmosphere of nervousness at the club.
"New strategy and new connections between players. Everything needs time."