Hamburg has been knocked out of the DFB Pokal by fourth-tier opposition -- just months after securing their Bundesliga status in the relegation playoff.
Bruno Labbadia's side looked set to be heading out in normal time until Michael Gregoritsch's 94th minute equalizer secured another 30 minutes of anguish for Hamburg fans.
But 19-year-old Johannes Pieles beat Emir Spahic to a cross ball in the 106th minute to score a famous goal for the East Germans whose fans invaded the pitch in delight at the final whistle.
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It is more misery for Hamburg who evidently has serious work to do before next week's season opener at Bayern Munich.
Justin Gerlach's free-kick from 30 yards on 15 minutes showed the inadequacies of Hamburg's current goalkeeper Rene Adler.
Breaking down their well-drilled opponents was difficult for Labbadia's men, and highlights the need for further investment to prevent the club's first relegation from the Bundesliga this season.
Hamburg levelled through Ivicia Olic on 48 minutes, but Jena â one of the famous East German sides of a bygone era -- hit a deserved second 10 minutes later when Velimir Jovanovic rounded off a fine counterattacking goal to put the hosts back in front.
As the clock ticked towards the inevitable conclusion of HSV's first-round exit, a long ball into the box â which included the committed goalie Adler in support -- fell to one of the more promising summer signings, 21-year-old Gregoritsch who scored his first goal for the club.
The home side somehow found a supply-after-supply of energy, outrunning the Bundesliga side and looking sharper over the small distances. Pieles rose quicker than veteran Spahic and headed in the winning goal to leave Hamburg nursing another embarrassing defeat.
Earlier, Borussia Dortmund returned from European success in midweek to narrowly beat third-tier Chemnitz 2-0 with Henrikh Mkhitaryan scoring his fourth goal in two games.
Mkhitaryan hit a hat-trick versus Wolfsberg in UEFA Europa League action and scored the second to kill the tie, his assist for Pierre-Emerick Aubameyang in the first-half setting Dortmund on their way.
Thomas Tuchel started with the same core as Thursday evening, although Gonzalo Castro and Sven Bender played from the beginning. After the cobwebs had been brushed off, Dortmund created chances around the 18-minute mark when Aubameyang's tame effort from 15 meters missed the target.
However, the Gabon international would break the deadlock on 25 minutes, the striker heading in Henrikh Mkhitaryan's pin-point cross from the left-hand side. The pair combined five minutes later with the Armenian enjoying his role on the left-side of a 4-3-3 formation.
Chemnitz could have equalized soon after, though, as Danneberg beat the offside trap but dragged his shot yards wide of Roman Burki's post. At the other end, Castro hit the woodwork on 38 minutes as Dortmund struggled to turn their dominance into goals.
But Tuchel's men dropped the pace after the interval, which was a similar problem in the first leg of their European tie with Wolfsberg. Chemnitz grew in stature and confidence and forced Burki into some meaningful action.
The goalkeeper from Switzerland was forced into a fine save from Chemnitz skipper Anton Fink with 15 minutes left as it threatened to be a nervy finish for Dortmund. The yellow-and-blacks could relax not long after when Mkhitaryan showed composure to curl the ball into the net from 12 yards on 83 minutes.
VfL Bochum, meanwhile, is the talk of the 2.Bundesliga after an impressive start to the season -- and they made little weather of dispatching Salmrohr with Simon Terrode scoring a hat-trick. Freiburg's Nils Petersen made it eight in three for the season, scoring four times to help beat Barmbek-Uhlenhorst.
Sunday's late matches see Bayern Munich take on FC Nottingen in Karlsruhe's Wildparkstadion, whilst fireworks are expected when Fortuna Dusseldorf and Rot-Weiss Essen meet.