Giovanni Trapattoni's reign as Republic of Ireland boss hurtled into crisis with the defeat.
The 73-year-old headed into what was always likely to be an intensely difficult World Cup qualifier with question marks hanging over his ability to take Ireland forward, and emerged from it with his band of critics having increased markedly in number.
Ireland were simply overpowered by the team ranked second in the world with Marco Reus firing them into a 2-0 half-time lead before Mesut Ozil, Miroslav Klose and a double from substitute Toni Kroos completed the rout.
There was delighted applause from a capacity crowd when substitute Andy Keogh headed home in injury time, but the consolation was minimal.
Neither Trapattoni's job nor Ireland qualification hopes were ever likely to rest on what they did against the Germans, but the soul-destroying manner of the heaviest defeat of his tenure, which heaped further misery upon the shortcomings of their Euro 2012 campaign, set alarm bells ringing.
Deprived of the services of the retired Shay Given and Damien Duff and the injured Richard Dunne, Sean St Ledger, Glenn Whelan, Kevin Doyle and Robbie Keane, Trapattoni's understudies simply never got to grips with a technically superior team.
Tuesday's trip to the Faroe Islands, who suffered a narrow home defeat at the hands of Sweden earlier tonight, now represents a key fixture for a man whose honeymoon period is now a distant memory.
It was a measure of the changes wrought on Trapattoni's squad by retirement and injury that the team which ran out against Italy in Poznan in Ireland's final game at Euro 2012 boasted a total 721 caps; tonight's team had mustered just 268 between them before kick-off, and 136 of those belonged to John O'Shea and Aiden McGeady.
After several days of a will-he-won't-he debate over Trapattoni's indication that he might opt to play three men in central midfield, the Italian did just that.
His reasoning was two-fold: an extra body in their might just help his side retain possession better, and one of the trio could attempt to shadow dangerman Ozil.
The game started relatively positively for the Republic when lone striker Jon Walters laid off Keiren Westwood's clearance to Keith Andrews and he dragged his shot from distance wide.
But that proved to be a rarity as the Germans eased into their stride and started to dictate the play.
With Ozil and Thomas Muller buzzing around behind frontman Klose and Reus threatening down the left, their movement was simply too much for Ireland, who too often found themselves chasing shadows.
They soaked up the early pressure and in truth, Westwood had little to do, watching Stephen Ward slice a seventh-minute Muller cross over his own bar and Darren O'Dea block Klose's shot on the turn 11 minutes later.
But as the pressure mounted, Ireland sank deeper and deeper towards their own goal to leave Walters isolated and invite the visitors on to them.
Reus was booked for diving inside the Ireland penalty area on the half-hour after Simon Cox, Coleman and O'Shea had failed to clear their lines, but he did not have to wait long to erase his disappointment.
With Coleman having drifted out of position, Bastian Schweinsteiger played the ball over the top of both the Everton man and the covering McGeady to full-back Marcel Schmelzer, and he cut inside to set up Reus, whose right-footed shot flew past Westwood and went in off the underside of the crossbar.
Trapattoni's men had hardly had time to swallow their disappointment when their task became almost impossible eight minutes later as Germany once again carved them open.
Full-back Jerome Boateng's crossfield pass arrived perfectly for Reus to smash a left-footed drive across Westwood and into the bottom corner.
Any hope of an unlikely fightback died in a disastrous start to the second half which saw Germany cruelly turn the screw.
Cox and Walters had both gone close to reducing the deficit in an early flurry, but order was soon restored when, after O'Dea had crudely felled Klose inside the penalty area, Ozil sent Westwood the wrong way from the spot with 55 minutes gone.
If the Sunderland goalkeeper had been under-employed for much of the first half, he was chronically exposed after the break and conceded for a fourth time within three minutes when Klose ran on to Schweinsteiger's tailor-made pass and rounded him before slotting into an empty net.
The Republic had capitulated in horrific fashion, and did so once again three minutes later when O'Shea's weak clearance fell perfectly for Kroos to help himself with a skidding shot inside the post.
Kroos deepened the wounds with seven minutes remaining, drilling home from 22 yards with the Republic in disarray and Trapattoni facing a grilling.