Andy Awford rued Pompey’s carelessness after slumping to a fifth successive away defeat.
The Blues found themselves behind after just 80 seconds to Shamir Fenelon at Tranmere this afternoon.
Yet Jed Wallace levelled in the 57th minute with his 11th goal of the season.
That sparked a purple patch for the visitors, only for James Rowe to restore the strugglers’ advantage 10 minutes later.
Max Power completed the 3-1 scoreline in the 77th minute after his penalty was initially saved.
Afterwards, Awford was left to reflect on another miserable away day,
He said: ‘When it went 1-1 it looked like only one team going to go on and win it – and it looked like it was going to be us.
‘We got back into the game after conceding so early and then thrown it away again.
‘It is very frustrating, of course it is.
‘Conceding after 80 seconds is the last thing we wanted and that’s what we got, but we didn’t crumble.
‘We stayed in the match which was better than previous away performances.
‘We sorted a few bits out at half-time and got back in it and then were in our ascendancy – but they went on and scored twice.’