Pompey scored twice in the second half to battle from behind against rivals Southampton and reach the semi-finals of the Hampshire Cup.
Chloe Newton gave the visitors the lead, only for Shannon Albuery to level the scores after the interval.
And the Blues booked their place in the last four of the competition thanks to a fantastic strike from Alex Collighan.
Jay Sadler made one change from the side that saw off C&K Basildon in the league the previous week, with Jaime Rowlands replacing the cup-tied Hannah Haughton between the sticks.
An all-time record crowd of 546 packed into the PMC Stadium in eager anticipation of the latest south coast derby.
And they witnessed an even start to the tie, with both sides enjoying spells of possession in the opening stages.
But it was Southampton who broke the deadlock on 19 minutes, as Newton finished her surging run into the box with a low finish into the bottom corner.
The hosts went in search of an instant reply, with Ellie Kirby – yet to open her account for the club – firing over after Collighan’s effort had been blocked.
Collighan was involved again moments later following some neat passing play from Rachel Panting and Albuery, but her shot went just off target.
Pompey did have the ball in the back of the net when Panting converted Albuery’s low cross, only for an assistant’s flag to halt the celebrations.
They continued to search for openings before the break and the lively Jade Bradley saw a couple of set-pieces headed wide.
Half Time: Pompey 0 Southampton 1
It was – like the opening to the first half – proving to be a even contest between the sides following the restart.
But Caitlin Collighan – Alex’s sister – fired over for the away side, who were looking to double their advantage.
Instead it was the Blues who were next to find the back of the net, as ALBUERY arrived at the far post to turn home Panting’s low ball across the face of goal.
That seemed to give the hosts an injection of confidence and they started to provide more of a threat.
Katie James whipped in a dangerous free-kick from wide on the left, which was well claimed by keeper Kayla Rendell.
But the added pressure paid off as Pompey found a winner on 82 minutes – courtesy of a real moment of magic.
Albuery laid the ball back for COLLIGHAN just inside the area and she curled a fine shot right into the top corner.
With Southampton now having to push players forward, the game was becoming an extremely open affair.
The home fans appealed for a penalty following a challenge on Albuery, but the referee disagreed and waved play on.
And they almost added to their lead deep into stoppage-time when EJ May’s clever pass found Albuery, who saw her shot saved.
The Blues remained strong at the back as the seconds ticked down, however, seeing out the final moments to book their place in the last four.
Pompey: Rowlands; Kirby, Southgate (c), Tonks, Currie; Bradley, Rowe; Albuery, James (Perkins 84), Collighan (Younger 90); Panting (May 90+2)
Sadler’s side return to National League action next Sunday when they make the trip to Coventry United (2pm kick-off).