In an horrific opening nine minutes, Josef Bursik had saved a penalty and Paik Seung-Ho had netted a free header from a corner as John Mousinho’s men were steamrollered.
Yet somehow it remained 1-0 at half-time, yet the hosts then added further goals through Tomoki Iwata, Christophe Klarer and Keshi Anderson.
Remarkably, the visiting fans continued to sing through as their team were battered during a miserable second half – and here are our Pompey player ratings...
9. Mark Kosznovszky - 4
Handed second league start after replacing Chaplin on the right flank, which is not his favoured position either. Has a decent engine and good work-rate, but never got into the match. Had Pompey's only shot on target in the 90th minute. Photo: Simon Roe
10. John Swift - 4
(Replaced by Conor Chaplin on 67 minutes) Restored straight to the side following suspension and, in attacking situations during the last 20 minutes of first half, had some nice touches. Yet Pompey’s problems were defensively, rendering him ineffective. Photo: Dennis Goodwin
11. Minhyeok Yang - 3
(Replaced by Josh Murphy on 53 minutes) Really struggled defensively with Bowat down Pompey’s left for the majority of the first half. On top of that, barely made a dent in attack. Anonymous yet abysmal. Photo: Graham Hunt
12. Makenzie Kirk - 4
(Replaced by Colby Bishop on 53 minutes) Retained his place and willing to chase lost causes, but had absolutely nothing to work with, let alone any goal-scoring opportunity. Photo: Graham Hunt