The former defender conceded the Mariners were second best during Saturday’s clash, especially in an opening 45 minutes which Pompey dominated.
While the hosts were able to show more threat after the break, Bignot found it difficult to understand why his men couldn’t respond to the fervent atmosphere created by both sets of supporters.
He said: ‘We had a great crowd here and, first half, I was very disappointed if I’m being honest.
‘I think it’s really easy to play here with the supporters because if you try to do the right thing they’ll back you.
‘I think in terms of our decision-making first half, everything we did wasn’t to my liking, it wasn’t to the supporters’ liking.
‘We never gave them anything to get behind them, not a tackle, not a run, not a positive pass.
‘Portsmouth are a good team, let’s not take that away, but the first half lacked the performance that warranted the atmosphere that was created by both sets of supporters.
‘We’ve gone against a team in Portsmouth and for how disappointing we were from a tactical and technical point of view, to come in at half-time 0-0 was a blessing.’
Bignot also pinpointed his side’s sloppiness in the build-up to the free-kick which allowed Kal Naismith to fire home Pompey’s 86th-minute winner.
He said: ‘You saw the lead-up to their goal was comical,. We’ve had possession of the ball on the right-hand side and then from nowhere it gets to opposite side of the pitch.
‘Again, they know about my restarts and due diligence, and it’s a throw-in that is just a simple roll. It’s a free-kick and then there’s your quality.
‘The actual execution of the free-kick was the difference.’
– HOWARD FROST