The writing appeared to be on the wall yet again for Mainz when they fell two goals behind within 22 minutes, Kevin Volland and Roberto Firmino both netting their fifth goals of the season.
However, substitute Eric Choupo-Moting pulled a goal back and a stroke of luck at just the right moment, with the ball hitting Malli and going in, earned Mainz a 2-2 draw.
Thirty-six goals have been netted in Hoffenheim's seven games so far this season so it was no surprise that it was another open game.
Both sides had chances to break the deadlock with Tarik Elyounoussi striking an effort against the bar before the visitors went in front in the 14th minute.
Volland came in from the right and was not challenged by four Mainz defenders, who simply invited him to shoot and score.
It was two in the 22nd minute when Sven Schipplock took the ball past two opponents down the right before feeding Firmino, who chipped the ball over the onrushing Heinz Muller.
Choupo-Moting was sent on by Mainz coach Thomas Tuchel in a bid to avert a fifth straight Bundesliga defeat.
The tactical change made an immediate difference with Shinji Okazaki getting in the hosts' first shot on target within minutes and the Japanese forward's trickery helped them create further chances.
Choupo-Moting scored with a low shot into the bottom left-hand corner, giving Mainz eight minutes to find an equaliser.
Shawn Parker thought he had found it in the 86th minute, but his celebrations were cut short by the offside flag.
Mainz goalkeeper Muller raced forward for a corner in the final minute of the game and he got a header in. The ball was cleared by Beck, but it hit Malli and rebounded in without the Mainz substitute really knowing anything about his second goal of the season.