Reuters
After two 1-0 wins, Chelsea endured a tough opening half hour when the Spanish side hit three on-target shots to none before dominating for the first time in this season's tournament.
Kalou had already had an effort saved and caused a freak goal by Frank Lampard to be ruled out for offside before he connected with Ashley Cole's 41st-minute cross along the edge of the six-yard box to send a shot high into the net.
Kalou, who was filling in for his suspended Ivory Coast teammate Didier Drogba, headed in a corner 11 minutes later before Lampard made it 3-0 in the 69th and Luis Perea headed in an injury-time own goal.
Chelsea has a maximum nine points in Group D, eight more than Atletico.
