A long kick out from Lukas Raeder, making his first league start in goal, allowed Mandzukic to seal the win with his 18th goal of the season. Only Dortmund’s Robert Lewandowski, who will replace or challenge the Croat for a starting place next season, has as many goals.
Lewandowski scored again against Mainz as Dortmund assured itself of at least third place.
Milos Jojic got Dortmund underway in the sixth minute with a 20-meter shot that took a deflection from Oliver Kirch’s right hand. TV replays showed the Dortmund defender tried to take his arm out of the way.
Shinji Okazaki equalized with another deflected effort in the 14th, but Lewandowski restored the home side’s lead four minutes later, when Henrikh Mkhitaryan set up the Poland striker to finish coolly.
Okazaki intercepted an inexplicable back-pass from Nuri Sahin to equalize again in the 54th, but Lukasz Piszczek made it 3-2 to Dortmund three minutes later, with a backward header from Marco Reus’ free kick.
Reus then secured the result from the penalty spot in the 79th, after Niko Bungert was sent off for blocking Lewandowski’s goalward shot with his arm.
“It was outstanding what my squad delivered today,” Dortmund coach Juergen Klopp said. “Another nine points from the last three games and everything is well.”
Freiburg denied Moenchengladbach the chance to go provisionally fourth, with the game turning after Freiburg goalkeeper Oliver Baumann saved Filip Daems’ penalty and Moenchengladbach midfielder Granit Xhaka was sent off for his second booking with the score still 1-1.