Danny Cowley’s men were undone twice on the counter in the first half as they fell to a 2-1 defeat at Fratton Park, in front of a crowd of 14,958.
That puts the focus firmly on adding attacking reinforcements over the rest of the transfer window.
Pompey were asking all the early questions and should have been in front after eight minutes, when Ogilvie blazed over from four yards with the goal at his mercy from Sean Raggett’s header back across goal.
Ronan Curtis then dragged a shot wide before the visitors took the lead against the run of play after 20 minutes, as in-demand Matt O’Riley threaded the ball through to former Blues target Mo Eisa who slipped the ball past Gavin Bazunu.
Harness then fired wide before teeing up Curtis who should have scored, but took a terrible touch before shooting allowing Jamie Cumming to tip over.
Pompey’s wasted chances returned to haunt them at the end of the half, as Scott Twine’s shot was blocked and Theo Corbeanu blazed home the loose ball from the edge of the box via the crossbar.
It was the home side asking the questions after the break, but Pompey couldn’t quite find the final pass or delivery as angst grew among the home crowd.
Ogilvie battled to win the ball in the 57th minute before looping a cross in which Hirst couldn’t quite reach. The visitors responded through Corbeanu’s drive which Bazunu pushed away.
Pompey were back in it with 30 minutes left as Hirst’s first-time finish finds the back of the net from Kieron Freeman’s cross
But for all the home side’s late pressure they couldn’t find a leveller with impressive sub Louis Thompson miscuing in the box, Cumming superbly saved Ogilvie’s header and John Marquis having a goal ruled out for offside in stoppage time.