Pompey boss Harry Redknapp was forced to make a pre-match defensive reshuffle as Andy O'Brien was ruled out after a calf injury failed to heal and in his place came club captain Dejan Stefanovic, returning after a five-week absence.
Pompey, with three wins out of three, looked full of confidence early on and throughout the entire first half dominated the game.
Blackburn, bidding for a Champions League spot for the first time in ten years, looked laboured as Andres D'Alessandro and Lua Lua tormented them.
It was a D'Alessandro cross inside the first two minutes which led to the first chance of the game, but when Sean Davis failed to control the ball in front of goal, Steven Reid made a timely interception.
From the resulting corner Pedro Mendes lashed a volley just wide.
Fifteen minutes later Gary O'Neil out-muscled Michael Gray on the right-hand side and crossed for D'Alessandro but the Argentine midfielder scuffed his chance wide.
Full-back Brian Priske, showing why Italian giants Sampdoria are interested in him, drove towards the by-line and crossed again for D'Alessandro who was hanging back at the far post and, after his volley was clawed out by Brad Friedel in the Blackburn goal, Mendes fired another volley just wide.
Pompey continued to press the Blackburn back four and LuaLua was guilty of being greedy on 23 minutes when his right-foot effort from a tight angle was saved by Friedal but the Congo striker should have pulled the ball back to Benjani Mwaruwari.
Nine minutes later though Bellamy was to confound Pompey's early dominance as Mendes lost the ball to Robbie Savage in the middle of the park. The Welsh striker was able to progress with pace past a sluggish Stefanovic and flat-footed Linvoy Primus before curling a delightful finish into the far corner which Dean Kiely could do little about.
The much-maligned Benjani was guilty of wasting the best chance of the half five minutes before the break as D'Alessandro's majestic ball over the top found the Zimbabwean striker but he and team-mate O'Neil got into a muddle and as the ball broke, Pompey's record buy simply fired his effort straight at Friedel.
Two minutes later the home side deservedly levelled. A poor corner from the right by D'Alessandro was picked up by Lu Lua who shrugged off challenges from Savage and Zurab Khizanishvili as he tip-toed along the 18-yard line before curling the ball into the far corner and celebrating with three back-flips.
Blackburn boss Mark Hughes pulled off Michael Gray at the interval replacing him with Aaron Mokoena and Rovers began to look more like the Champions League contenders they were billed as.
David Bentley, who had a poor first half, moved into midfield and it was his run that set up Bellamy's and Blackburn's second. The former Arsenal youngster drove a right-footed cross into the Welsh striker's path and, as he turned onto his left foot, Primus stood off and the ball flew into the top corner.
Thirteen minutes later Stefanovic missed an even better chance than Benjani's first-half effort as he somehow headed over unmarked from three yards from a D'Alessandro free-kick.
Substitute striker Todorov showed the Serb the way to goal two minutes later as Matthew Taylor skipped inside Mokoena and delivered a perfect cross for the Bulgarian to level.
Blackburn thought they'd won it at the death but referee Steve Bennett spotted Brett Emerton's blatant handball at the far post.