Many pundits make Barca favourites to beat the Blues and advance to their third Champions League final in four seasons, but Kalou is adamant Pep Guardiola's defence has enough flaws to offer hope of eliminating the holders.
While Barca's strength lies in the world-class skill of Lionel Messi, Andres Iniesta and Xavi, Ivory Coast star Kalou is less impressed with their back-four.
"They have their weaknesses," Kalou said. "We know that they haven't been so confident at the back, conceding a lot of goals, so that is something we can play on.
"People see the way Barcelona play today and they can say, 'Chelsea have no chance against Barcelona'.
"But, as a player for Chelsea, we work hard every day in training and we believe that on the pitch is the only way of answering all those negative thoughts. Our fans expect us to win, we expect to win."
Although Barcelona are rightly regarded as Europe's preeminent force at present, Kalou points to their failure to keep pace with Jose Mourinho's Real Madrid in the Spanish league this term as proof they are not invincible.
"Everyone forgets that Madrid are having a great season with Jose," Kalou said.
"Right now, if we had played Madrid, people would not say that Chelsea has no chance.
"But, because it's Barca, because they have Messi and all those players, people are thinking that we can't make it.
"The Chelsea players know that this is one game and, in one game, everything can happen."
Kalou and his team-mates also have the added motivation of wanting to avenge their highly controversial defeat in the last meeting in the 2009 Champions League semi-final.
The Blues had several strong penalty appeals turned down before Iniesta scored the decisive away goal in stoppage-time.
Kalou, who was an unused substitute that night, recalls the match vividly.
Speaking on the Stamford Bridge touchline and pointing to the spot where Iniesta scored, he said: "It was right here, Iniesta's goal.
"I think that time we deserved to go through because we had a lot of chances, we had a couple of penalties.
"There are teams like that. You play them and they always win, but there is a moment when you also can overcome them."
Source: AFP
Source: AFP