Substitute Liam Walker earned Pompey a point as they fought back to grab a 1-1 draw with Carlisle.
The midfielder stepped up to equalise from the penalty spot in the 78th minute after fellow substitute John Akinde had been felled by keeper Mark Gillespie.
Carlisle struck the post through a Jon-Paul McGovern free-kick in the first half, but took the lead on 51 minutes through Rory Loy after poor Pompey defending.
The hosts struggled to even raise a shot on goal in their attempts to drag themselves back on level terms.
Then came Walker’s spot-kick to get a draw, although Pompey have still to win in their past 21 games.
Hartlepool’s 2-1 win at home to Leyton Orient also meant the Blues are now bottom of League One.
Guy Whittingham named an unchanged side following Pompey’s goalless draw at Hartlepool in midweek.
That meant Shaun Cooper continuing at right-back in place of Yassin Moutaouakil, while Sam Sodje retained his place in the centre of defence.
When the game got under way, in the ninth minute Dan Butler slid through a first-time pass from the left flank.
However, it was agonisingly just out of reach from the on-rushing Jed Wallace’s outstretched boot and the keeper gathered.
James Keene then produced a wonderful piece of skill, juggling the ball past several players inside the box before it bounced away from him.
Pompey had good fortune moments later when McGovern’s 30-yard free-kick struck the right-hand post, ricocheted off Simon Eastwood and somehow stayed out
It was goalless at the interval but within minutes of the restart a magnificent flying save from Eastwood kept out Liam Noble’s fiercely-struck volley from outside the box.
But Carlisle did take the lead in the 51st minute when Lee Miller had time to control and spin, sliding through a pass for Loy.
The striker took the ball around on-rushing Eastwood and slotted into the empty net, despite Sodje’s best attempts to stop it going in..
By the 62nd minute Pompey had used all three of their substitutions, with Akinde, Walker and Moutaouakil all on the field.
In a rare attempt on goal, Walker did have a left-foot shot from dlong istance in the 73rd minute, but it curled harmlessly wide.
Yet in the 78th minute Pompey did level when Walker netted from the penalty spot after Gillespie brought down Akinde.
Patrick Agyemang was the architect for the move, beautifully controlling the ball with back to goal before spinning round and setting Akinde free inside the box.
That was enough to take a point and make it successive draws for Whittingham’s men.
POMPEY 1 (Walker pen 78)
CARLISLE 1 (Loy 51)
Pompey: Eastwood, Cooper (Moutaouakil 38), Sodje, Rocha, Butler; Reed, Ertl (c), Racon, Wallace (Walker 62), Agyemang, Keene (Akinde 62). Subs: Smith, Webster, Gyepes, Harris.
Carlisle: Gillespie, Simek, Robson, Livesey, O’Hanlon, McGovern, Noble (Symington 77), Thirlwell, Berrett, Loy, Miller. Subs: Colin, Murhpy, Welsh, Potts, Cadamarteri, Beck.
Referee: Carl Berry (Surrey)