After a difficult few days for the under-pressure German, a Friday night outing against another side newly relegated from the Premier League promised a potential respite.
Instead, a game that began amid a heavy shower ended with the boos once again raining down from the stands as the Terriers crashed to yet another home defeat.
Within the hour, Siewert’s eight-month reign had been terminated. His record of just one win and 15 defeats from 19 games prompted new owner Phil Hodgkinson to act.
What must have made his axing all the more galling for Siewert was that the loss to Fulham was again self-inflicted. As with the 2-1 defeat against Derby County that had kicked off the campaign, the opening goal came via the sort of calamitous individual error that typified much of Siewert’s time at the helm.
Juninho Bacuna was culpable this time, the Dutch midfielder somehow managing to turn what should have been a simple clearance in a non-threatening position into a simple tap-in for Aleksandar Mitrovic.
Karlan Grant did restore parity soon after but a sublime finish from Ivan Cavaleiro 10 minutes from time ensured justice was done on a night when Kamil Grabara had been by far the busier of the two goalkeepers.
It meant Siewert headed down the tunnel at the final whistle with the jeers ringing in his ears, just as he had on Tuesday after Huddersfield’s limp Carabao Cup exit to Lincoln City.
That loss sparked speculation that the 36-year-old was on his way. The talk proved premature but his reprieve proved short-lived thanks to a defeat that was far more emphatic than the final score suggested.
After a first half littered with mistakes by both teams, the Londoners took control on the restart. Scott Parker’s men had 17 efforts on goal to just six by the hosts, eight of which were on target.
Tellingly, Town tested Marcus Bettinelli in the visitors’ goal just once and that was when Grant equalised.
His bullet header just before the hour did, at least, improve the number of goals from open play in 18 league games under Siewert to seven.
That, though, was little comfort after another chastening night that had seen the Yorkshire club once again commit footballing suicide. Tommy Elphick had been the guilty party against Derby by gifting Tom Lawence the opener. Bacuna’s mistake last night was, if anything, even worse.
There was little danger as an arrowed cross eventually found the Town midfielder more or less on the goal-line but out towards the left-hand flank. A lazy swing of the leg later, however, and the ball was looping back towards goal and Mitrovic, who could not believe his luck, the Serbian nodding into an empty net.
The breakthrough may have come in bizarre circumstances. But it had been coming, Fulham having twice gone close in the early stages of the second half. First, Mitrovic looked to have been played in by Cavaleiro only for Christopher Schindler to execute an inch-perfect tackle.
Then, after Tommy Elphick had denied Stefan Johansen a shooting opportunity when well placed, Grabara beat away an Anthony Knockaert effort.
Town drew level just before the hour. Flo Hadergjonaj created the opportunity with a telling right-wing cross but it was the neck muscles of Grant that proved too much for Bettinelli.
Linesman Jonathan Hunt did not flag that the ball had crossed the line but a buzz of referee James Linington’s watch was enough to send the home fans into raptures.
The joy, however, was not to last. Fulham continued to dominate, as Knockaert brought a save from Grabara.
Steven Sessegnon was the next to be denied by the Liverpool loanee, while Jonathan Hogg had to take a booking for the team by tripping Mitrovic as he scampered clear.
Fulham, however, would not be denied victory. Mitrovic, collecting a pass from Sessegnon inside the six-yard box, did well to keep the ball alive before finding Cavaleiro.
The Wolverhampton Wanderers loanee had wasted perhaps the best opening of an error- ridden first half by ignoring better placed team-mates to drill a low shot that Grabara had saved.
This time, though, Cavaleiro was calmness personified as he looked up before curling a quiet exquisite shot beyond the Town goalkeeper and bring the curtain down on Siewert’s troubled reign.
Huddersfield Town: Grabara; Hadergjonaj, Elphick, Schindler, Kongolo; Bacuna (Chalobah 54), Hogg, O’Brien; Kachunga (Mounie 83), Grant, Pritchard (Van la Parra 84). Unused substitutes: Schofield, Diakhaby, Bockhorn, Quaner.
Fulham: Bettinelli; Sessegnon, Mawson, Ream, Bryan; Cairney, Arter, Johansen (Decordova-Reid 76); Knockaert (Le Marchand 90), Mitrovic, Cavaleiro (Reed 84). Unused substitutes: Rodak, McDonald,, Christie, Kamara.
Referee: J Linington (Isle of Wight).