Conor Chaplin netted a last-minute winner to give Pompey their first victory under Paul Cook.
This afternoon’s friendly at Gosport appeared to be heading for a 2-2 draw after the visitors conceded two goals in two minutes.
Cook changed his entire side for the Privett Park fixture following last night’s trip to the Rocks, yet they found themselves in a 2-0 win by the 66th minute.
A first-half Chaplin strike and triallist Theo Robinson’s first goal for the club confirmed their superiority.
Yet in the 73rd minute Justin Bennett reduced the deficit when he took advantage of hesitancy in the Blues’ defence to prod substitute Steve Ramsey’s pass Michael Poke.
Then two minutes later it was level when substitute Jamie White calmly slotted past Poke from the angle.
That appeared to be it, until Jayden Stockley crossed from the left and Chaplin slotted home to seal the victory.