Holders Barca, who won last month's Champions League last-16 first leg in Leverkusen 3-1, have conceded just five goals in 13 home La Liga games this season and let in only two at the Nou Camp in their three group matches in Europe's elite competition.
A big reason opponents find it so difficult to score against Pep Guardiola's side is that they rarely go a game without having the ball for at least 70 percent of the time, their mesmerising passing game grinding teams into submission.
In Europe's top five leagues, Barca playmaker Xavi has completed by far the most passes in the opponents' half this season with 1,553, Barca's website said.
Their World Player of the Year Lionel Messi, Champions League top scorer this term with seven goals, is second with 1,351 passes while full-back Daniel Alves is fourth on 1,215 - sandwiched between Real Madrid's Xabi Alonso with 1,271 and Arsenal's Mikel Arteta on 1,207.
"The fact that it is a tough prospect is clear to all of us but it's not over until it's over, as the saying goes, and we'll wait and see what happens," Leverkusen forward Stefan Kiessling said in an interview on the club's website.
"We want to go there and do ourselves justice and look for our chances."
SPECIAL WIN
The size of the task that faces the Germans is underlined by the fact that Barca are unbeaten in 13 European home matches since October 2009, with 11 wins and two draws, while Leverkusen are without an away victory in the competition in a decade.
However, they could not have wished for a better dress rehearsal for the trip to the Catalan capital after Kiessling scored in a 2-0 win against Bayern Munich on Saturday - their third straight league success.
Barca, missing the suspended Messi, had Gerard Pique sent off just after half-time at home to La Liga strugglers Sporting Gijon on Saturday but managed to grind out a 3-1 victory thanks to goals from Andres Iniesta, Seydou Keita and Xavi.
"To win against Bayern is special," Leverkusen coach Robin Dutt said.
"If we continue playing like we have done in the past few weeks then the results will come.
"Of course it's going to be tough to win 3-0 in Barcelona but I don't think it makes any sense to think about that.
"First of all we have to play a good game, there will be 4,000 fans coming with us to Barcelona and whether we get through or not we owe it to them to play well."
Dutt used two strikers against Bayern, switching to a 4-4-2 formation in the second half when they scored both goals.
Switzerland forward Eren Derdiyok has recovered from an injury picked up on international duty last week and even made a substitute appearance against the Bavarians.
Barca will be without Alexis Sanchez, who scored twice in the first leg, after the Chile forward damaged an adductor muscle in the Gijon game and will be sidelined for between 10 and 15 days.
Fullback Eric Abidal picked u
