Although the hosts started on the front foot, they went behind after 15 minutes thanks to a remarkable early Christmas gift from Kauã Santos.
The Eintracht goalkeeper sold Ellyes Skhiri short with a pass and the midfielder was forced to lunge at the ball, sending it looping back towards his own goal. Santos had plenty of time to deal with it but appeared confused as to whether he could handle the ball or not, and after a moment of hesitation, he panicked and could only punch the ball into his own net.
Moments later, it appeared that Nadiem Amiri decided to return the gift after a needless lunge on Skhiri resulted in a straight red card.
In the aftermath, it seemed that the game’s pattern was set with the hosts completely dominating, but they were caught out with another sucker punch midway through the half.
A hopeful punt forward found Paul Nebel, who optimistically let fly from distance, and his shot took a big deflection to wrong-foot Santos as the visitors doubled their lead.
The hosts tried to get back into the game before the break and had a golden chance as the ball fell to Omar Marmoush in the box, but he uncharacteristically spooned the ball over the bar from close range.
Marmoush had another golden chance for a tap-in just after the restart when he was picked out by Oscar Højlund, yet he somehow mishit the ball straight at Robin Zentner.
Although the visitors weren’t actively attacking, they weren’t in a mood to reject any further gifts from Santos as his poor backpass put Frankfurt under pressure, allowing Nebel to eventually slam home his second goal of the game.
Just when it looked like all hope was lost, Rasmus Kristensen headed home with 15 minutes to go, but there was to be no heroic comeback as Mainz rise to fifth place in the league after five wins in six games, while Eintracht remain two points ahead in third spot.
Flashscore Man of the Match: Paul Nebel (FSV Mainz)