Kenny Jackett pinpointed creativity problems as Pompey suffered a dismal defeat at Wycombe.
Adebayo Akinfenwa’s 83rd-minute penalty settled matters at Adams Park, earning the League One highfliers a 1-0 victory.
It immediately prompted chants of ‘We want Jackett out’ from some of the 2,125 travelling support.
Both teams had been reduced to 10 men on 55 minutes when Nnamdi Ofoborh and Ellis Harrison were dismissed.
Nonetheless, the Blues were lacklustre throughout and produced one of their poorest displays of a season which has now yielded just one win in seven League One matches.
And Jackett acknowledged their weakness as an attacking force against the Chairboys.
He said: ‘Today we battled quite well, we didn’t shirk, particularly our two centre-backs, they stood up quite well.
‘My feeling was go with Tom Naylor back into midfield with Ben Close, which has been quite a successful one for me, and to see if that could give us some stability in the team.
‘While we stood up to the physical nature of it, our centre-backs had good games, we didn't do anywhere near enough going forward.
‘We are better than that, we are more flowing than that, we can create more chances than that – and ultimately that was the frustration for me.
‘If you look at our results, which are the bottom line, we have won one out of seven league games, that’s our third away loss now, which is frustrating, definitely.
‘While we scrapped away and were always in it, we didn’t do enough going forward, we didn't have enough chances and didn’t show enough composure and creativity.’