Hoping to avoid a repeat of their 3-2 loss at the Volksparkstadion earlier in the season, Bremen experienced the first flurry of chances, though Daniel Heuer Fernandes was equal to efforts from Cameron Puertas and Justin Njinmah.
Hamburg looked to be in for a long afternoon, but they suddenly improved in the forward areas, and were unfortunate that Ransford-Yeboah Königsdörffer was offside prior to Robert Glatzel finding the net, before Mio Backhaus had no trouble in dealing with Fábio Vieira’s long-range strike.
The game’s end-to-end flow hadn’t been matched by the quality of finishing so far, but that abruptly changed in the 37th minute. Yukinari Sugawara capitalised on a missed clearance by Miro Muheim and floated in a cross from the right, where Jens Stage arrived unmarked to thunder a header past Heuer Fernandes.
The home faithful were in raptures at seeing their skipper score the opener against Hamburg for the second time this campaign, but they were fearing that another turnaround could be on the cards just minutes later.
A long ball down the right by Nicolás Capaldo was collected by Glatzel, who defied the tight angle by sending a rocket into the far top corner.
But this time the pendulum swung back the other way, and the hosts were back in front before the hour mark. Stage received a ball from Puertas on the edge of the area, and steadied himself before curling a right-footed strike into the top corner.
Hamburg’s response was subdued at best, but things got significantly worse for them when Philip Otele was shown a red card for staying on his feet when Puertas slid in underneath him.
Die Rothosen’s Bundesliga-highest eighth red card left them on the back foot, and there were even more riches for their opponents when Romano Schmid laid it off for Puertas to sweep inside the near post.
Daniel Thioune will be delighted to get one over his former employers, particularly as it gives them a five-point buffer to the bottom three. That’s the same margin as Hamburg’s own cushion from danger, though HSV’s now 10-match run without a clean sheet suggests that their trajectory may differ from Bremen’s as the endgame nears.