First-half goals from Pascal Groß and Markus Suttner, along with a second half Almog Cohen penalty, were enough to see FC Ingolstadt 04 earn a crucial three points in the key relegation battle against HSV at the Audi Sportpark on Matchday 18 in the Bundesliga.
In what was a lightning fast start to the match from Maik Walpurgis' side, a Groß half volley and Suttner free-kick had quickly gave the Bavarian side a two goal lead.
Half-time Hamburg substitute Dennis Diekmeier allowed Cohen to give die Schanzer a three goal lead, after giving away an early penalty, before Gotoku Sakai gave Markus Gisdol's side a lifeline with just under half an hour remaining.
But the hosts held on for what will prove a crucial three points in the quest for Bundesliga survival, as die Schanzer in the meanwhile leapfrog Hamburg in the standings.
Groß and Suttner quickly send Schanzer into the lead
In what was a crucial battle between two sides threatened with relegation, it was first blood to the hosts, FC Ingolstadt 04, with the game a little under a quarter of an hour old. A long looping ball into the Hamburg box was nodded down by Matthew Leckie into the path of Pascal Groß.
The 25-year-old cut across the ball and hit an effort on the half volley across Christian Mathenia's goal and into the far corner, leaving the former SV Darmstadt 98 goalkeeper with no chance as Maik Walpurgis' side took an early lead. Still, Hamburg nearly hit instantly back when Filip Kostic's deflected freekick nearly snuck past Ingolstadt 'keeper, Martin Hansen.
It was fine margins that had prevented die Rothosen from leveling the scores, and it would prove to be very fine margins that once again were at HSV's downfall as die Schanzer extended their lead shortly after.
It was Markus Suttner who benefited, as the Austrian international's left footed free-kick was deflected, leaving Mathenia wrong-footed as the ball dropped into the bottom right corner to send the Audi Sportpark crowd into jubilation.
The former Austria Vienna man's third goal from a set-piece this season, as well as Ingolstadt's sixth from a dead ball situation - a Bundesliga high.
The HSV central defensive duo of Mërgim Mavraj and Kyriakos Papadopoulos were both signed during the winter break, from 1. FC Köln and Bayer Leverkusen respectively, with the intention of shoring up what had been a leaky defence during the course of the first half of the season.
Only Werder Bremen have conceded more than die Rothosen, and the early signs had been positive with the pair one of the few positives in last weekend's defeat at VfL Wolfsburg. However in Bavaria, the pair had done nothing to ease Hamburg's defensive woes with Darío Lezcano and Leckie continually getting the better of the defensive combination.
Papadopoulos had resorted to hacking down the Australian international, Leckie, for which he received a yellow card, but unfortunately for die Schanzer the 25-year-old forward was unable to carry on.
Reverting to a back three, Ingolstadt's defence of Marvin Matip, Roger and Romain Brégerie had proved more than a match for whatever Hamburg could throw at them throughout the entire half. That came with usual first choice defender, Marcel Tisserand, still in African Cup of Nation's action for his native Democratic Republic of the Congo.
Gisdol's side did remind Ingolstadt that they were still in the game just before the half, but Hansen was at hand to get down well and send Bobby Wood's effort for a corner.
The Danish 'keeper has proved an integral part of die Schanzer's resurgence since Walpurgis took over from Markus Kauczinski in November, earning a number of plaudits especially in the victories over RB Leipzig and Leverkusen.
Cohen extends the lead, before Sakai makes it interesting
Attempting to change the game, Hamburger SV boss, Markus Gisdol, brought on both Dennis Diekmeier and Gideon Jung at the break.
It had the desired effect too, just at the wrong end, as after just forty-five seconds Diekmeier bundled over the Paraguayan Ingolstadt striker, Lezcano, and afforded FC Ingolstadt 04 the chance to obtain what would be an unassailable lead.
Almog Cohen stepped up and cooly sent the ball down the middle, after Mathenia had dived low to his right. Coincidentally, the Israeli had scored his first ever Bundesliga goal against die Rothosen all the way back in January 2011 in a 2-0 victory whilst at 1. FC Nürnberg.
Lezcano had been superb, despite his dearth of a goal. The man who joined Ingolstadt from Swiss side Luzern last January had ran his socks off, running both Mavraj and Papadopoulos ragged throughout.
The continued good performances of the Paraguayan will prove key for Maik Walpurgis, especially with the news that club talisman Moritz Hartmann will be absent for a number of weeks with a thigh problem.
Gotoku Sakai had only scored one goal in the Bundesliga, whilst at VfB Stuttgart, since coming to Germany from his native Japan in 2011. However the wait for a goal from the right back was well worth it, as he gave die Rothosen the faintest chance of a comeback with a little over half an hour remaining in Upper Bavaria.
Sakai picking the ball up from a good thirty or so yards out and launching a thunderous effort beyond Hansen, this time the Dane could do nothing to prevent the only ever present Bundesliga side from breaching the resolute Ingolstadt defence.
Despite the lifeline Sakai had given them, die Rothosen failed to really take the game by the scruff of the neck and put Walpurgis' side under any real pressure for the remainder of the match.
The Ingolstadt defence were able to deal with the limited threat that Bobby Wood and the remainder of the Hamburg attack could offer, whilst if anything it was the Bavarian side who threatened to extend their lead - Suttner blasting an effort just wide of Mathenia's post.
Nevertheless, die Schanzer were headed for a crucial three points in the relegation battle and would no longer hold the title of the worst home record in the Bundesliga, that mantra now falling to Markus Gisdol's HSV.