Steve Cotterill slammed poor defending as Pompey were thumped at Watford.
The Blues were undone by two second-half strikes after Andrew Taylor's peach of a volley sent the Hornets on their way.
Both goals after the restart saw Pompey's backline carved open after one of their players were caught in possession.
Cotterill lamented that fact after his men have been delivering on the road of late.
He said: 'The goals were poor. They split us easily.
'They were poor goals between our full-backs and centre-halves.
'We've played well away from home. Maybe, we were due a bad one.'
One piece of good news for Pompey was Liam Lawrence's loan move from Stoke becoming permanent.
But there are no developments on the contract situations surrounding Richard Hughes and Michael Brown.
Cotterill said: 'Liam Lawrence's transfer is permanent and he is available for Hull.
'There's no news on Richard Hughes and Michael Brown and I don't envisage there being any.'