The Blues’ head coach was exasperated after shipping in three goals in eight minutes during a second-half blitz.
It was 1-1 before Gavin Bazunu’s mistake gifted the hosts the chance to regain the lead on 55 minutes.
Subsequently, during that period, Michael Smith, Richard Wood and Ben Wiles all netted for the rampant hosts to effectively end the contest after 62 minutes.
Most Popular
-
1
'I don't think I realised how much it would mean': ex-Cardiff City and Bristol City man's Portsmouth admission as he chases winning Fratton feeling after homecoming
-
2
Latest: Key development in Portsmouth's attacker pursuit as Danny Cowley puts finishing touches to squad
-
3
The George Hirst conspiracy theories that had Portsmouth Twittersphere in meltdown – and what is next for Leicester front man also wanted by Ipswich
-
4
Former Portsmouth, Sunderland and Millwall ace Aiden O'Brien suffers setback as frustrating start to life at Shrewsbury continues
-
5
How golden boot odds have shifted for Portsmouth, Ipswich Town, Plymouth Argyle, Bristol Rovers and Peterborough United front men after start to season
And Cowley admitted he has concerns over his side’s ability to respond positively to set-backs.
He told The News: ‘Without doubt we are questioning our response to disappointment. I don’t think we respond in games particularly well as a group.
‘Gavin makes a mistake, but the response off the back of that is so disappointing for me because I just thought we went under.
‘We didn’t show anywhere near the durability and resilience you need to show in that moment of disappointment.
‘It was a bad time to concede (the second goal) but these things will happen, you have to overcome this.
‘Why didn’t they respond? These are the questions that we have to ask. If you want to be a successful team you must be durable.
‘You are going to get moments of disappointment, it’s elite sport. There will be moments individually and collectively that you have to ride those moments, you have to overcome those moments.
‘We didn’t do that.’
The Blues are now 12th following one win in 11 matches in all competitions.
Certainly, up until Bazunu’s mistake, it was panning out to be an encouraging display at the home of Rotherham.
That represented the game’s turning point – and Pompey’s worrying capitulation.
Now Tuesday brings Paul Cook’s Ipswich to Fratton Park, who are presently just one point behind the Blues.
Cowley added: ‘Ultimately three goals in eight minutes have cost us and, no matter what you have done prior to that, it has then gone.
‘We have actually played well up to 55 minutes, but that doesn’t win you a game of football – so we now have to go and feel the pain of a 4-1 reverse.’
A message from the Editor, Mark Waldron
You can support our local team of expert Pompey writers by subscribing here for all the latest news from Fratton Park for less than 13p a day