Borussia Monchengladbach's Champions League qualification hopes were dented as Christian Clemens' goal earned Mainz a 1-0 Bundesliga win.
Christian Clemens' first-half goal was enough to secure Mainz a 1-0 Bundesliga success at home to Champions League hopeful Borussia Monchengladbach.
Gladbach came into Friday's meeting at the Coface Arena fourth in the table - the final qualification berth for Europe's premier club competition - but suffered a second successive defeat since the resumption of the campaign.
The winner came midway through the opening period as Jairo Samperio's fine individual run ended in a pass to Clemens, who was afforded space 20 yards from goal.