After a cagey affair between both sides in the opening minutes, Kalou broke the deadlock on the half-hour mark with his third league goal of the campaign.
The Cote d'Ivoire international
The effort was the 33-year-old's sixth in 10 outings against the Borussia outfit, making them his favourite goalscoring opponents alongside Hannover 96.
6 - Salomon #Kalou has now scored six #Bundesliga goals against Mönchengladbach (in ten games), only against Hannover has he scored as many. Favourite. @HerthaBSC_EN #BMGBSC pic.twitter.com/ggtFLH8mUN— OptaFranz (@OptaFranz) February 9, 2019
After the interval, Ondrej Duda and Davie Selke sealed maximum points for the visitors in the 56th and 76th minutes respectively to secure their second league win in 2019.
The defeat for Borussia Monchengladbach was their first on home ground since the start of the 2018-19 league campaign.