The hosts currently occupy 11th with three wins from their nine games so far this season although their last home match saw them thrash Borussia Monchengladbach 4-0.
Mainz lie three points ahead with an Adam Szalai hat-trick guiding them to a 3-0 win over Hoffenheim last time out.
Bremen coach Thomas Schaaf, though, is only focusing on his side and is confident they should prevail.
"We are the favourites because we are at home and we are convinced about the strength of our team," said Schaaf, the league's longest-serving coach.
"We know what quality Mainz have too, but we are still concentrating on ourselves."
Mainz are equally confident ahead of their trip north to a place where they have won twice in a row without conceding a goal.
"We have faith in our ability to play well there," said coach Thomas Tuchel.
Hungarian Szalai will lead the line again on Sunday and Tuchel knows he will be in the spotlight.
"He is indispensable for us," he said. "I think the focus is on Adam because he scored three goals last weekend.
"Had he only scored one, he would still be as valuable to us, only there would have been fewer questions to answer."
Ivan Klasnic will not be able to face his former side since he is still recovering from injury and not yet in full training while Marco Caligiuri misses out for Mainz.