On the back of a brilliant showing last weekend against Angers where he scored to help his side to a 2-1 win, the 21-year-old continued the sparkling performance against the Red.
The visitors started the game in an uninspiring manner after referee Johann Hamel issued a straight red card to Romain Amalfitano for a serious foul offence.
Antoine Kombouare’s men managed to curtail the Girondins for 77 minutes before substitute Andreas Cornelius broke the deadlock, with Kalu providing the assist.
The 21-year-old winger featured for the entire duration of the game while his teammate and Guinea international Francois Kamano was withdrawn shortly after the hour mark.
With the win – their seventh this season - Bordeaux are 10th in the log with 28 points from 20 games. They travel to Stade de la Meinau to tackle Strasbourg on January 26.