Adam Szalai had the first opportunity of a slow-burning encounter, rifling an effort against the bar from 18 yards. Stefan Kießling could do no better at the other end, the Bundesliga's leading marksman scuffing straight at Christian Wetklo and heading wide in front of the watchful eyes of Germany coach Joachim Löw.
On the spot
A Manuel Friedrich handball gave Mainz the opportunity to land the first real blow from the penalty spot, and Ivanschitz duly obliged to put the hosts ahead with his sixth Bundesliga goal of the campaign.
The introduction of Sidney Sam did little to help the Leverkusen cause, as Mainz battled over the finish line and back into the European places. Die Werkself, meanwhile, stay third.
Line-ups and statistics