Pompey snaffled a point at Rochdale thanks to Matt Done’s stoppage-time own goal.
The Rochdale defender turned in Brett Pitman’s header to earn Kenny Jackett’s men a dramatic late 3-3 draw at Spotland.
It looked as if Ian Henderson’s 71st-minute finish would mean Pitman’s double counted for nothing at Spotland.
But the Blues battled to the death to make it five games unbeaten and collect what may well prove to be a critical point
Brad Inman put the home side in front in the 13th minute before Pitman levelled after a flowing counter.
Stephen Humphry’s and Henderson grabbed second-half goals either side of Pitman’s 62nd-minute finish.
Pompey failed to deal with the combative approach of Dale but their resolve was shown as their kept asking questions to the death and were rewarded.
Pitman failed to capitalise on the game’s first big chance as he headed over Pitman’s powerful cross from six yards in the 11th minute.
Pompey paid for that miss two minutes later as Inman cut in from the left and unleashed a 20 yarder, which arrowed into the far corner of Luke McGee’s net.
It could have got worse in the 23rd minute as Joseph Rafferty’s header looped over McGee from a corner, but Henderson applied a final touch from an offside position.
Pitman started and finished a lovely Pompey leveller in the 26th minute as he freed Jamal Lowe, who beat two blue shirts and crossed after losing his footing for the skipper to fire in at the back post.
Evans then fired a piledriver off the bar three minutes later before McGee saved impressively at Stephen Humphrys’ feet in the 36th minute.
Pompey were slow out of the blocks after the restart and were punished after 57 minutes when Humphrys grabbed the second.
Done provided the ball in from the left and the striker guided a fine 15-yard finish just inside McGee’s far post.
The reply came quickly as Pitman levelled in the 62nd minute, when he swivelled in a finish after Clarke met Dion Donohue’s free-kick and headed across the face of goal.
But failure to deal with Inman’s cross from the left saw Pompey punished in the 71st minute, as Calvin Andrew met the ball at the back post and Henderson bundled the ball home from a couple of yards.
From there, it was huffing and puffing from Jackett’s men but they never really looked like forcing a leveller.
That was until Whatmough put a 92nd-minute ball into the box, Pitman helped it on and Done applied an unfortunate final touch.