The 20-year-old had fired blanks in his first game for the Girondins as they bowed 2-1 to Toulouse in the French elite division opener.
Kalu came off the bench in the 75th minute for Zaydou Youssouf as they secured a valuable away point from the Ghelamco Arena in the play-off showdown.
And he looked sharp during his brief outing in a game that saw his team reduced to 10 men after Jules Kounde was sent off for a second caution.
Senegal's Younousse Sankhare was on for 90 minutes for Bordeaux, while Guinea's Francois Kamano got four minutes of action after replacing Nicolas De Preville.
A win for Kalu’s side in the return leg at Matmut Atlantique on August 30, with the winner on aggregate making it to the championship’s group stage.