كتب : Omar AbdelAziz
The Egyptian striker put his team ahead with a 21st minute penalty which was cancelled out by Diego Klimowitz's strike in the 41st minute.
Zidan thought he has won the game for Mainz when he fired in his second (79) but he saw his efforts shattered by a double from Brazilian forward, Marcelinho Paraiba, in the 80th and 87th minutes.
Zidan took his tally to 10 goals in 10 games with Mainz, lying 4th in the Bundesliga top scorer charts with a total of 11 goals this season.
The defeat caused a major slip-up in Mainz's league position dumping them from 13th to 17th place with only 30 points.
Elsewhere, all the big guns have eased to victories in the top of the table battle, as leaders Schalke comfortably beat bottom club Borussia M'gladbach 2-0 courtesy of Gerald Asamoah and Kevin Kuranyi goals.
Second-placed Stuttgart stunned HSV Hamburg 4-2 at home thanks to goals from Cacau, Sami Khedira, Roberto Hilbert and Fernando Meira, David Jarolim and Ivica Olic grabbed late consolations for the hosts.
Bayern came back from a goal down at Hannover to win 2-1 after goals from Martin Demichelis and Bastian Schweinsteiger erased Arnold Bruggink's strike.
Borussia Dortmund registered a crucial 4-1 away victory at Alemania Aachen to jump three positions to 13th place.
The relegation warfare remains tight with just three points separating 17th from 11th place.