Michael Appleton rued Pompey’s lack of killer instinct as they were battered by Burnley.
The Blues collapsed in the second half as they went down to a 5-1 beating.
Pompey were dominant in the opening period but went in level at the break as they failed to take advantage of finding themselves in a number of good positions.
They paid for that as Burnley took the lead 75 seconds after the restart.
Sub Charlie Austin then fired in a hat-trick as Pompey fell apart to leave them five points from safety in the Championship table.
Appleton said: ‘The first half was probably as good as Tuesday from a performance point of view.
‘We never took the opportunities created.
‘I was frustrated with their goal. We showed the players they do that a dozen times, so it’s frustrating.
‘They were clinical in the second half and we weren’t in the first. We got punished.
‘That doesn’t disguise the fact we lost too many of our personal battles.’