Mainz got a first taste of the Europa League two years ago while Hannover have spent the last two seasons competing in Europe.
Both sides are currently locked together on 20 points with Hannover lying sixth by virtue of their superior number of goals scored, and better goal difference over Hamburg and Borussia Monchengladbach.
The difference between being sixth and ninth is a big one, though, particularly psychologically, according to Hannover coach Mirko Slomka.
"When you are in sixth place at the end of a matchday, then it is a comfortable feeling," said Slomka.
"That means we've done a good job. We are enjoying playing in the Europa League again this season and we hope to experience it again next year."
Mainz may not be setting their sights on a return to Europe, but it is becoming an increasingly realistic goal.
They continue to take things one step at a time, hoping to pick up as many wins as possible since that makes it easier even to recharge the batteries after a midweek match.
"The atmosphere in training is completely different when you reward yourself with a win," said coach Thomas Tuchel.
"Otherwise, we don't change the way we train according to whether we win or lose."
With Adam Szalai scoring in the wrong goal in the 3-1 win over Eintracht Frankfurt on Tuesday, it was the turn of Shawn Parker, making his first start, to open his account at the other end.
"He deserved his chance," said Tuchel, who is pondering whether or not to field him again against Hannover.
"I am delighted when we are able to score three goals away from home and when we are not always dependent on Adam."