Gareth Ainsworth criticised the manner of the two goals which prevented his side defeating Pompey.
The Chairboys were 2-0 up heading into first-half stoppage time after strikes from Michael Harriman and Garry Thompson.
Come the 55th minute, it was 2-2 as the visitors stormed back.
Firstly, Christian Burgess launched a counter attack by feeding Marc McNulty, who squared for Caolan Lavery to net.
Then Adam Webster headed home Ben Davies’ corner from the right.
The match finished 2-2 – and Wycombe boss Ainsworth was disappointed in his team’s costly defending.
He said: ‘They were disappointing goals to concede. We were wide open for the first one, they’re disappointing for us to concede because we don’t concede that type of goal.
‘It’s just a lack of concentration and a sucker punch right before half-time and the second one from a corner is poor defending from us.
‘The first one is the sloppiest goal, a clearance where we haven’t come out together, you’ve got to get your units close and together before you start pushing out and we pushed out too far apart. Against players of that calibre you’re going to get punished.
‘There are two young kids, two really young kids, three if you count Jason McCarthy at right back, and mistakes are few and far between which is fantastic.
‘There’s not many 19, 20, 21 year olds in the country who don’t make mistakes and they really limit their mistakes.
‘It’s a little bit of a lack of concentration and tiredness. We have to make sure they are fresh not just in the body but mentally as well.’
Ainsworth, however, was full of praise for the impressive Michael Harriman, on loan from QPR.
He added: ‘He’s a really special player. He was outstanding. His energy levels for somebody who is a loan player is just ridiculous.
– NEIL ALLEN