When the final whistle sounded to confirm their 1-0 win at Sandhausen, Hamburg thought they had just sealed a return to the Bundesliga after five long years in Germany's second tier.
Their ecstatic supporters, dreaming of life back in the big time next season, stormed onto the pitch in jubilation after securing what they believed was a second-place finish in 2. Bundesliga and automatic promotion to the top flight.
Rivals Heidenheim, one point ahead going into Sunday's finale, were trailing 2-1 away at Jahn Regensburg deep into stoppage time, meaning even a late equaliser would not have been enough to keep hold of their automatic spot.
Yet as they let off flares and hugged one another on the pitch with promotion seemingly in the bag, disaster struck for Hamburg fans. Heidenheim produced a sensational last-gasp comeback, scoring twice in the final six minutes of stoppage time to break Die Rothosen hearts.
Jan-Niklas Beste's penalty first brought Heidenheim level in the 93rd minute, before Tim Kleindienst popped up at the back post in the 99th minute of the game to snatch promotion back from Hamburg right at the death.
And more still, Darmstadt's 4-0 defeat away at Furth meant Heidenheim even leapfrogged the former into first place to head up to the top flight as second-division champions.
It was an astonishing end to the 2. Bundesliga title race, with Hamburg supporters left devastated on the pitch in Sandhausen.
Kleindienst's late goal means they now must contest this season's promotion playoff, which pits them against 16th-place Bundesliga side Stuttgart.
The first leg will go ahead at Stuttgart’s Mercedes-Benz Arena on Thursday, 1 June, before the decider takes place at Hamburg’s Volksparkstadion on Monday, 5 June.
Hamburg boss Tim Walter said after their gut-wrenching defeat in the race for automatic promotion: 'We did our job today, but so did Heidenheim.
'Accordingly, we congratulate you on your promotion. Of course we're disappointed, but we're well prepared for the [play-off].
'We will put a powerful squad on the field and want to have the upper hand this year.'
