Hoffenheim picked up their first win since December and only their second since September with the odd goal in five seeing them past Mainz.
Jhon Cordoba gave Mainz the lead, but Eduardo Vargas selflessly teed up Nadiem Amiri to bring the hosts level within two minutes.
Hoffenheim took the lead in the 68th minute with Kevin Volland getting in around the back of the Mainz defence and pulling the ball back for Mark Uth to score.
Uth appeared to put the result beyond doubt 15 minutes from time when he again got on the end of a low cross, this time from the right from Pavel Kaderabek, but Jairo Samperio made things interesting just a few minutes later when he picked out the top left-hand corner from the edge of the penalty area.
Hoffenheim nevertheless held on to move to within two points of Werder Bremen in the relegation play-off berth, while denting Mainz's European qualification hopes.