The two sides come together for the first leg of the encounter at Stamford Bridge on Wednesday, with the former English champions heading into the clash off the back of a 5-1 FA Cup semi-final win over Tottenham Hotspur.
"From the start of every game, it's 50-50," said Lampard. "Barcelona are favourites because of the players they have in their team but if we play like we did against Spurs in the two games then we will have a chance.
"It gives us confidence. We have to carry that on. Any team's beatable. They are the best, but we can't show too much fear. We have to take them on and I think we can do it."