Guy Whittingham spoke of his frustration at the costly defensive error at Mansfield and admitted: One mistake is all it takes.
Phil Smith’s collision with Joe Devera and Bondz N’Gala for an unopposed cross meant Pompey had to settle for a 2-2 draw on Saturday.
Substitute Lindon Meikle profited from the mistake to salvage a point for the Stags.
Goals from Andy Barcham and David Connolly turned a first-half deficit on its head at Field Mill.
Pompey withstood a second-half aerial bombardment from the home side.
It looked like they were set to hold firm and pick up their first maximum on the road.
That made the manner of Mansfield’s equaliser tough to take for Whittingham.
He said ‘It’s obviously frustrating.
‘They put us under a lot of pressure but we defended well. They put the ball into the box whenever they can.
‘We largely dealt with that but then we have let them get back into the game.
‘We coped but then there was the one lapse – but that’s all it takes.
‘We should have kept the lead. It’s easy to say from the sidelines (it should have been dealt with) but Bondz and Joe are in there trying to win it and Phil is trying to get it.
‘They all wanted to win the ball.
‘That’s what they did for the majority of the game.’
Mansfield gave Pompey a hostile welcome with the home fans making themselves heard and Whittingham insisted that is something Pompey must get used to.
He said ‘We’ve come away to a very hard place to come and ended up drawing the game.
‘But we have to learn to cope with the pressure because it will happen every time we go away.’