Robert Lewandowski's opener looked to have undone the away side's excellent early work, but a swift equaliser from Rudnevs set the tone for a pulsating encounter. Son's spectacular left-foot strike put the northerners in front, but red cards for Lewandowski and HSV's Jeffrey Bruma made for a heated duel which was eventually settled when Rudnevs and Son each completed braces in the second period.
Credit had to go to Hamburg for the way they piled towards the intimidating Yellow Wall from the off. It was shock-and-awe from Thorsten Fink's men, who pinned the champions back for much of the early stages and first seriously threatened when Dennis Diekmeier's run and cross from the right was met by an audacious overhead kick from Son. However, with 14 minutes gone Roman Weidenfeller made the save.
Dortmund were never likely to lay dormant for long and just seconds later Mario Götze put inches wide after collecting Lukas Piszczek's cross on the chest. It was a warning HSV failed to heed as Lewandowski fired the hosts in front minutes later, seizing on a high ball which Heiko Westermann failed to deal with before rounding Rene Adler and slotting into the empty net for his 14th of the season.
However, Dortmund had barely finished celebrating by the time Hamburg had drawn level. A quick ball down the left from Marcell Jansen released Dennis Aogo to cross for Rudnevs to tuck in at the near post. Buoyed by the equaliser, the Red Shorts almost went in front when Son grazed the post from a tight angle after rounding Weidenfeller, and the South Korean soon made good on his threat.
After shimmying past the stranded Mats Hummels, Son cut in from the right before executing a wonderful curling shot which caught the inside of the post on its way past a bewildered Weidenfeller. With just 26 minutes gone it had already become quite the encounter, and the drama wasn't to end there as Lewandowski was dismissed for a wild challenge on Per Cilian Skjelbred.
Doubles for duo
Doomed to contest the final hour a man short, the Yellow-Blacks did their best to find an immediate response. Götze thought he'd levelled things on the stroke of half-time only for his provider, Marco Reus, to be flagged for offside. The ten men continued to create opportunities in the second half, with Hummels lofting onto the roof of the net after remaining forward from a corner, and their chances took a major turn for the better when Bruma was sent off for bringing down Reus as he raced through on goal.
At least so they thought. Minutes later the visitors pulled another surprise out of the bag as van der Vaart sent in a tantalising cross in from the left which Rudnevs rose to meet and extend Hamburg's tally. In an enthralling final fifteen, Dortmund threw everything forward, but there was no way back for the titleholders, especially after Son slid home his second from Jansen's centre late on.
Line-ups and statistics