Dortmund and Schalke both beaten
Karim Bellarabi scored the quickest goal in Bundesliga history and then set up another for Stefan Kiessling as Bayer Leverkusen stunned hosts Borussia Dortmund with a 2-0 win on Saturday evening.
Bellarabi struck after only nine seconds, beating the previous quickest goals scored by Giovane Elber and Ulf Kirsten by two seconds to leave the Westfalenstadion shellshocked.
He then teed up Kiessling for the second deep into second-half stoppage time with Leverkusen proving to be good value for their win in Roger Schmidt's first game in charge.
Hannover came from behind to beat Schalke 2-1 to increase the pressure on the Royal Blues' coach Jens Keller.
Klaas-Jan Huntelaar gave the visitors the lead in the two minutes after the half-time interval after a dreary first 45 minutes at the Niedersachsenstadion.
But two goals in three minutes from Edgar Prib and Joselu turned the game on its head, earning Hannover all three points and condemning Schalke to a second defeat in a week, after they lost to Dynamo Dresden in the first round of the DFB-Pokal.
The Bundesliga season may only be a day old, but already Keller will have to listen to rumours surrounding his future.
Julian Schieber's fourth brace of his Bundesliga career was not enough to earn Hertha Berlin victory as they surrendered a two-goal lead to draw 2-2 with Werder Bremen at the Olympiastadion.
The former Borussia Dortmund forward gave the hosts what seemed to be a comfortable lead with goals in either half, but Assani Lukimya and Franco Di Santo scored two goals in as many minutes to earn Robin Dutt's men a share of the spoils.
A crowd of almost 60,000 left the Olympiastadion disappointed after seeing their side throw away what looked set to be a winning start to the season.
Schieber joined Berlin this summer as a replacement for Adrian Ramos, who moved to Borussia Dortmund.
Hoffenheim began their campaign with a 2-0 win over Augsburg.
Adam Szalai marked his debut with a goal before Tarik Elyounoussi added a second just two minutes later.
Augsburg, who lost in the first round of the DFB-Pokal last weekend, tried to find a route back into the game in the second half, but they came up against a well-drilled Hoffenheim defence.
Haris Seferovic's goal was enough for Eintracht Frankfurt to make a winning start to the season, beating Freiburg 1-0 at the Waldstadion.
The much-travelled Swiss forward, who last season represented Real Sociedad after spells in Switzerland and Italy, opened his Frankfurt account after just 15 minutes, and that proved to be enough to see off Freiburg.
The visitors played their part in the game, though, and were unfortunate not to return home with a point at least.
A crowd of 50,000 at the Mungersdorfer Stadion watched Cologne play out a goalless draw with Hamburg on their return to the top flight.
Chances were at a premium in what seemed more like a preseason warmup match than the first appointment of what could be a long and hard season for both sides.