Dermot Drummy admitted a combination of Pompey’s intensity and the Fratton Park occasion killed Crawley.
Three first-half goals buried the Red as Paul Cook’s side ran out comfortable 3-0 winners on Saturday.
Drummy had no complaints over the outcome as the Blues’ pressing and tempo did the damage in front of 16,347 fans.
Drummy told the Crawley Observer: ‘We’ve come to one of the strong favourites to go up and got well beaten.
‘Portsmouth’s movement, their pressing and their fans, it’s some place to come, it’s some atmosphere here.
‘The plan was initially to sit and to try and hit them on the counter-attack, but I think sloppy play giving two goals away put them in the driving seat for the game.
‘And then the third one just before half-time has killed us.
‘You’ve got to have that bravery to play, not suicidal into their midfield block, that’s when you should be going in behind.
‘In the first half they pressed us and we still didn’t turn them around, we still tried to play poor balls and not good quality balls.’
Drummy was pleased with the changes he made in the second half – even if he knew the contest was over.
He said: ‘Josh Payne came in the middle and kept the ball a lot better.
‘Bobson (Bawling) up front gave us a spark and Jason (Banton) on the left with Chris Arthur there gave us more emphasis going forward. But they were content to contain us.’
Alex Davey’s mistake proved a Crawley blow as Danny Rose robbed him allowing Gary Roberts to score, but Drummy refused to be critical.
He said: ‘It’s a learning curve, that’s life.
‘You will see a few of those on the telly over the weekend but he has to pick himself up and there were others who weren’t playing the way I want around the back either.
‘Some people don’t want the ball at times and they don’t make space for people.’
– JORDAN CROSS