Adi Huetter’s side held a three-point cushion in the fourth and final Champions League spot heading into last weekend’s round of matches, but were thrashed 6-1 at fifth-placed Bayern Leverkusen before exiting the Europa League semi-finals to Chelsea on penalties in midweek.
Eintracht knew a win over Mainz would restore their two-point advantage in fourth ahead of their final league game at title-chasing Bayern Munich.
But their European exertions got the better of them as Nigerian international Anthony Ujah scored twice in four second-half minutes for Mainz to leave Frankfurt sixth, a point adrift of fourth-placed Borussia Moenchengladbach.
They will now have to beat Bayern next week, potentially handing the title to Borussia Dortmund, and hope both Gladbach and Leverkusen drop points.
“We just haven’t taken the opportunity to play in Europe next year, but now we have to give everything in Bavaria,” said defender Martin Hinteregger, who missed his spot-kick against Chelsea.
“We can win a lot, but we can also lose a lot.”
On Saturday, Bayern’s bid for a seventh straight league crown was pushed to the final day of the season as Niko Kovac’s men were held to a goalless draw at RB Leipzig, while Dortmund moved to within two points of their rivals thanks to a nervy 3-2 victory over Fortuna Duesseldorf.
