Paul Cook admitted it was the Home Park moment which ‘broke his heart’.
But the need to show respect was never going to prevent him entering that Plymouth dressing room.
Peter Hartley’s stoppage-time goal condemned the Blues to League Two for a fourth consecutive season.
It was play-off heartbreak for Pompey, with the joyous home crowd invading the pitch at the final whistle to celebrate.
Tears were shed among the Blues players as they reflected on missing out on promotion during a season which promised so much.
As for Cook, he opted to visit the Pilgrims’ dressing room to deliver his personal congratulations.
The benches have endured a fractious relationship during the four encounters this season.
But Cook was adamant that had to be put aside – irrespective of a stinging defeat.
He said: ‘You have got to have manners.
‘I go back to when I was manager of Sligo in Ireland and we got to the FAI Cup final for the first time in 15 years.
‘There were 8,000 present – 7,000 from Sligo – with the whole stadium red and white, and we played Sporting Fingal.
‘We were 1-0 up after 82 minutes and got beat 2-1, the winner arriving in stoppage time, but I did the same and went into the opposition dressing room.
‘You speak to your players and say “When it is our day nobody will ever stop us having it”. But if you can’t take defeat then you are not going to be a good winner.
‘On Sunday night it broke my heart to go into that dressing room and say what I did, but I meant it.
‘I went in on my own and told them to have a great day out at Wembley, to go and see it through now and get promotion, that they were up there for a long time.
‘I walked out and they gave me a clap.
‘Next year when it is us – and I believe it will be us, that is how you have to think – then I can’t look back and say I didn’t show any gratitude when it was me.
‘People see the hostilities between managers and I don’t think they realise sometimes it is not like that, it shouldn’t be like that for me.
‘If we are going to have a game of football, a game we all love, we must show more respect to each other, even in technical areas.’
Meanwhile, Cook is awaiting Football Association developments on his altercation with Pilgrims first-team coach Paul Wotton.
The two were sent to the stands after clashing in Thursday’s first leg at Fratton Park – but were able to remain in their respective benches for the return.