Leipzig hangs on Bayern Munich at the top of the Bundesliga and that thanks to Emil Forsberg.
After 70 minutes, he replaced Kevin Kampl with an offensive line and in the 70th minute it paid off.
Forsberg stood at the penalty area line, surrounded by Union Berlin defenders.
He wall-played with Dani Olmo and scored the winning goal behind Andreas Luthe.
The 1-0 victory means that the distance up to Bayern Munich is still four points.
Leipzig is second in the table.
The goal was Forsberg's fourth in 17 games this season.