(CNN) -- Wolfsburg threw away a three-goal lead and three points against Mainz, Saturday, as Steve McClaren's team went down 4-3 in a pulsating match at the Volkswagen Arena.
A brace from Edin Dzeko saw Wolfsburg take a 2-0 lead and Diego, the Brazilian playmaker, added a third after 30 minutes. It looked like the goal would mark a successful return for the Brazilian to the Bundesliga after an indifferent season at Juventus.
But goals either side of half-time by Danish striker, Morten Rasmussen and Colombian midfielder, Elkin Soto put Mainz right back in the game.
Andre Schuerrle leveled the scores in the 58th minute, before Hungarian striker, Adam Szalai sealed a famous comeback. The defeat leaves the former England coach, McClaren without any points after two games.
Last season's runners-up, Schalke also crashed to defeat at home to Hannover.
Hannover defender Konstantin Rausch opened the scoring after 31 minutes with striker Mohammed Abdellaoue adding a second in the 49th minute.
Jermaine Jones gave Schalke a glimmer of hope when he scored in the 82nd minute, but it was too little too late for Felix Magath's team who, like Wolfsburg, remain pointless.
Hamburg came from behind to defeat Eintracht Frankfurt 3-1 at the Commerzbank Arena.
Halil Altintop gave Frankfurt the lead in the 38th minute. But Dutch defender Joris Mathijsen equalized for Hamburg in the 61st minute.
Ruud van Nistelrooy added a second nine minutes from time - his third goal in two games -- and Peruvian Jose Paolo Guerrero sealed the three points moments before the final whistle.
Werder Bremen inflicted a 4-2 defeat on Cologne to repair some of the damage of their 4-1 defeat they suffered at the hands of Hoffenheim on the opening weekend.
Senegalese striker, Demba Cisse scored twice for Freiburg as they came from behind to beat Nuremberg 2-1 at the Frankenstadion.
The biggest shock of the weekend came on Friday evening when newly-promoted Kaiserslautern stunned German champions Bayern Munich with a 2-0 win to continue their 100 percent record this season and top the table on goal difference ahead of Mainz, Hamburg and Hanover.
Bayer Leverkusen host Borussia Moenchengladbach and VfB Stuttgart take on Borussia Dortmund on Sunday.