Leverkusen rebounded from going behind to Marcel Sabitzer’s opener when Kai Havertz equalised on the stroke of half-time, and Brandt – who last week signed a new deal until 2021 – was the inspiration for second-half domination, putting Leverkusen in front before setting up goals for Panagiotis Retsos’ and Kevin Volland.
Victory for Heiko Herrlich’s men, which was their first over Leipzig in the top flight, lifts them into fourth in the table and the last qualification spot for next season’s UEFA Champions League.
The host broke the deadlock on the stroke of half-time with Sabitzer finishing after a slickly executed one-two with Yussuf Poulsen.
Leon Bailey led a speedy Leverkusen counter-attack to set up Havertz to volley home the equaliser, and it was 2-1 shortly after the break when Brandt collected Bernd Leno’s goal-kick, slipped around the opposition defence and blasted into the bottom-right corner.
The Germany international then deflected a free-kick into the path of Retsos to score his first Bundesliga goal, and laid on the assist for Volland to score his 50th Bundesliga goal and end a drought that stretches back to 12 January.