After Pal Dardai’s men played a goalless draw with Wolfsburg in their last game, they started the tie against the Foals on an impressive note with the Cote d'Ivoire international putting them in front in the 40th minute.
However, they failed to build on the lead as Thorgan Hazard’s second-half brace halted their aim of securing the maximum points.
Hazard scored in the 75th minute to cancel out Kalou‘s opener after benefitting from Josip Drmic’s assist. He then completed his brace four minutes later from the penalty spot.
The former Chelsea player was replaced by Alexander Esswein with nine minutes left to play.
Despite the defeat, Hertha Berlin occupy the tenth spot in the league log with 36 points from 39 outings.
Kalou has now scored 11 goals in 26 top-flight appearances this season and will be looking to continue the goalscoring form when the Olympia Stadion outfit play host to Koln on April 14.