"This is a classic David versus Goliath duel which has nothing to do with the league. But I am sure we will put in a very good performance," Leverkusen captain Simon Rolfes told reporters on Monday ahead of the first leg in Germany.
Champions League holders Barcelona stumbled to a 3-2 defeat at Osasuna on Saturday that left them 10 points adrift of leaders Real Madrid in La Liga but Leverkusen coach Robin Dutt warned that meant little.
"Barcelona play a spectacular offensive game but also outstanding pressing game," Dutt said. "It would be nice to go into the second leg with the tie still open."
"I would also be satisfied with a 5-0 straight win but that is not realistic," he said with a grin.
"But we are a team that does not give up. We can cause real problems for top teams and we have shown that," he said.
Leverkusen won all their home games in the group stage to advance but have been disappointing in the Bundesliga, in sixth place 15 points off the top.
They will take on the Spaniards, who rested many of their starting players on the weekend, without out-of-favour midfielder Michael Ballack, injured in training on Sunday.
"He will be out for three to four weeks but even if he was not injured we would likely not play differently [against Barcelona]," said Dutt of the former Germany captain, who is set to leave at the end of the season.
