Six of Mainz’s seven points this season have come on the road, and their home form looked set to worsen as they were 2-0 down after just nine minutes.
First, a Leverkusen cross from the left was headed away by Philipp Mwene, but only as far as Robert Andrich, who, from 20 yards out, caught it with the purest of volleys that flew past the goalkeeper and was still rising as it hit the net.
Then, the visitors were flying when Ibrahim Maza cleverly let Aleix Garcia’s through ball run on to Patrik Schick, who turned his marker and slotted his fifth of the season into the bottom corner.
But Urs Fischer’s side then took control of the game and were back in it just past the half-hour mark, when Eric Martel headed a corner goalwards, and though Andrich made a block on the line, Anthony Caci reacted quickest to bundle it home.
That gave Die Nullfunfer renewed belief, and they completed the comeback three minutes before half-time.
After a series of blocked shots, Nadiem Amiri found Caci on the right side of the area, and the Frenchman cut inside and curled his second of the game around Mark Flekken, continuing his side’s run of scoring at least twice in every match this season.
Mainz hadn’t scored in both halves in any of their previous six home matches. The Amiri-Caci partnership nearly ended that run within four minutes of the restart, but following a one-two, Amiri bent his strike just past the post.
On the flipside, Bayer then took their streak of scoring in successive halves to 11 matches, when Jarell Quansah struck the ball straight at Alexander Schwolow, only to loop the rebound over the goalkeeper with his head.
VAR checked the goal for a potential handball in the build-up by Schick, but it was allowed to stand.
Just as in the first half, the away side made it a quickfire double, as Afonso Moreira drove at the Mainz defence before squaring to Moussa Diaby, who unleashed a wonderful strike in off the top corner from the edge of the box.
Unlike in the first half, Mainz didn’t respond well to conceding a second, and Leverkusen’s travelling fans were instead wondering how Martin Terrier didn’t put their side 5-2 up, before Amiri was wasteful from range.
Carles Martinez Novell’s side have taken their unbeaten run in this head-to-head to seven matches (W5) and move up into the top four, while Mainz missed the chance to reach 10 points after six top-flight matches for the first time since 2010, despite Benedict Hollerbach tucking away a consolation in the dying seconds.
Flashscore Man of the Match: Anthony Caci (Mainz)