Derek Adams was adamant not being awarded penalties led to his side's downfall at Pompey.
The Plymouth boss felt his side had a claim for THREE first-half penalties as they were comfortably put to the sword by Kenny Jackett's side.
And the Scot clung on finishing above the Blues in two seasons, either side of losing out on the League Two title on final day of the 2016-17 campaign.
Adams centred his claims on Freddie Ladapo not being awarded a penalty following a collision with Craig MacGillivray, after he fired wide in the 22nd minute.
He suggested there were further spot-kick shouts his side were could've been awarded, as they were taken apart by Pompey's attacking quality.
Adams told Plymouth Live: 'It was a stonewall penalty against Freddie Ladapo.
'There were another two penalty claims in the first half.
'If they are given then it’s a different ball game.
'The advantage then went to Portsmouth and they got their goals after that.
'It really hinged on the decision in the first half. It was a clear penalty kick.
'I saw it from the great view that I had. Freddie had put the ball over the goalkeeper and the goalkeeper went right into him.'
Adams was keen to highlight the league positions of Pompey and Plymouth in recent seasons.
He pointed to finishing above the Blues in the 2015-16 season, when both sides failed in the League Two play-offs after the Pilgrims' semi-final win at Home Park.
The 43-year-old also trumpeted finishing seventh to Pompey's eighth, as both teams missed out on the top six last term, as a triumph.
It was a thread maintained on Plymouth's Twitter account, as they pointed out their club had finished above Pompey in four of the last five seasons.
The tweet failed to mention the Blues being above the Pilgrims in English football for the previous 24 campaigns, however.
Adams added: 'Portsmouth have only finished above me once in my three years at this football club, and that was the last game of the season (in 2016-17).
'So they can have their day today, and rightly so, they have won 3-0. They are in buoyant mood.
'But they have just got to remember that we have finished above them twice out of three seasons.'