Also on Wednesday, Bayer Leverkusen completed the signing of former Bayern Munich goalkeeper Michael Rensing, who was released by Cologne following their relegation last season.
Mainz went ahead in the 25th minute with Ivanschitz scoring his first goal in German football, although Bayern goalkeeper Michael Rensing must accept some of the blame.
Bance then scored his second goal in as many games -- beating Daniel van Buyten in the air to head Florian Heller's right-wing cross past Rensing from eight yards out.
The Austrian's low shot towards the bottom corner was within Rensing's reach, but he only got a very weak hand to it and helped the ball into the back of the net.
Routledge almost broke the deadlock after the restart but fizzed a 20-yard effort against the post and Nigel Reo-Coker burst through on goal only to once again be denied by the defiant Rensing.