Substitute Svetoslav Todorov salvaged a potentially priceless point for Portsmouth and dented Blackburn's Champions League hopes in the process.
Todorov came up with a potentially priceless equaliser
Todorov met Matthew Taylor's near-post cross to earn a share after Craig Bellamy had twice put Blackburn ahead.
Bellamy burst from his own half to put Rovers ahead only for Lomano LuaLua to level with a fine individual strike.
Welsh striker Bellamy looked like grabbing all three points for Rovers when he finished David Bentley's cross.
Portsmouth almost made a dream start as Andres D'Alessandro's first-minute cross found Sean Davis six yards out, but his failure to control allowed Robbie Savage to clear for a corner.
D'Alessandro screwed a first-time shot wide when he had time to control Gary O'Neil's cross and the Argentine then saw his low cross deflect off Ryan Nelsen into Brad Friedel's arms.
Freidel reacted superbly to parry D'Alessandro's deflected shot and the ball was only half-cleared to Pedro Mendes who fired inches wide from 18 yards.
The big American keeper then denied LuaLua at his near post, although the DR Congo striker might have done better by pulling the ball back to waiting team-mates.
After being on the back foot Blackburn took the lead out of the blue on 32 minutes with a magnificent individual goal by Bellamy.
Pedro Mendes was caught in possession by Savage who fed Bellamy, yards inside his own half. The Welsh striker took off at top speed and outpaced Linvoy Primus before lashing a left-foot shot from a tight angle across Dean Kiely.
Benjani had a golden chance to level when he found himself 12 yards out in front of goal, but Pompey's record signing drove his shot straight at Freidel.
Pompey drew level with a superb goal from LuaLua, who worked his way across the 18-yard box before finding space to curl a shot just inside the post.
LuaLua almost opened the second half in spectacular style when he collected Benjani's pass in the inside-left channel and squeezed a shot past Freidel and watched it roll inches wide of the far post.
Bellamy scored two superb goals
A wonderful open game was developing into a personal duel between former Newcastle team-mates LuaLua and Bellamy and the Blackburn striker produced another superb strike to put his side ahead.
Bentley was allowed to carry the ball down the right flank where he cut the ball back to Bellamy, who was given time and space by Linvoy Primus to turn and shoot left-footed past Kiely.
Pedro Mendes' free-kick found Dejan Stefanovic unmarked but the Pompey skipper headed over from four yards.
But substitute Todorov did better when he got on the end of Taylor's near post cross to nod the equaliser.
Portsmouth mounted a grandstand finish to find a winner and Stefanovic was denied again by a superb save from Freidel.
Portsmouth boss Harry Redknapp:
"This was two points lost for us because we murdered them for half an hour before Craig Bellamy scored a world class goal for them.
"We've won our last three games but it was the best we've played in those games.
"We went behind twice and showed great character in equalising both times which is something we wouldn't have done a couple of months ago."
Blackburn manager Mark Hughes:
"Fratton Park is a difficult place to come, so it was a positive that we got our noses in front.
"But it was a negative that we were not able to protect the lead and we feel hard done by that we didn't win.
"Portsmouth are fighting for their lives in the Premiership and credit to them they put us under pressure and came from behind twice."
Portsmouth: Kiely, Priske, Primus, Stefanovic, Taylor, O'Neil, Davis (Routledge 68), Pedro Mendes, D'Alessandro, LuaLua, Mwaruwari (Todorov 68).
Subs Not Used: Ashdown, Karadas, Hughes.
Booked: Pedro Mendes.
Goals: LuaLua 41, Todorov 78.
Blackburn: Friedel, Neill, Nelsen, Khizanishvili, Gray (Mokoena 45), Bentley, Reid, Savage, Pedersen (Emerton 82), Dickov, Bellamy.
Subs Not Used: Enckelman, Kuqi, Sinama Pongolle.
Booked: Dickov, Bellamy, Emerton.
Goals: Bellamy 32, 62.
Ref: S Bennett (Kent).