David Lopez netted from the penalty spot in the sixth minute of injury time to salvage a point for the Seagulls.
It was a forgettable game at Ewood Park, with few opening for both sides, but Albion looked like they were going home from the north-west empty handed following a first-half spot kick from Jordan Rhodes.
But with just seconds remaining, David Goodwillie bundled into the back of David Lopez and referee Robert Madley pointed straight to the spot. The Spaniard dusted himself down and calmly sent Rovers keeper Jake Kean the wrong way as he found the bottom right corner of the net.
Albion were also indebted to Tomasz Kuszczak who made two fantastic stops to deny the hosts; more than redeeming himself for his mistake at St Andrew's.
Albion made the brighter start as they stamped their authority on the game while Blackburn seemed content to sit back and try to catch the Seagulls out on their counter-attack.
Former Spain international Vicente - starting his first league game of the season – was quick into the action as he caused the Rovers defence problems, beating right-back Todd Kane to get a cross in from the left before whipping in an inviting ball from the right moments later, but both deliveries evaded the Albion strikeforce.
But Blackburn’s superior height advantage was evident in the Albion box, when combined with Morten Gamst Pedersen’s trademark long balls into the area.
Indeed it was the Norwegian international’s free-kick which picked out Scott Dann six yards out but his header deflected wide of the Albion goal off the back of Inigo Calderon.
Gus Poyet’s side were enjoying the better of the possession but it was Kuszczak who was called into action on 15 minutes when £8m man Rhodes and former Albion striker Colin Kazim-Richards linked-up well. The latter picked out midfielder Jason Lowe who stabbed the ball at goal but Kuszczak was equal to the effort, pulling off a terrific saved low to his right.
Wayne Bridge left Kane in his wake down the left before delivering a dangerous ball into the box, which was flicked on by Andrea Orlandi, before Barnes guided the ball narrowly over the bar with a glancing header. Moments later Liam Bridcutt saw his curling 20-yard effort fall narrowly wide of Kean’s left post.
At the other end Pedersen also struck a well-timed volley at the Albion goal which was beaten away to safety by the Seagulls stopper.
But on the brink of half-time came the break through and it went in favour of the home side; Markus Olsson delivered yet another long ball into the Albion box, which was too deep for everyone, yet Pedersen went down after colliding with Adam El-Abd
The referee’s assistant took his time before flagging for a foul which was quickly followed by Madley pointing to the spot.
There were strong appeals from the Albion camp but in-form striker Rhodes stepped up and slotted the ball into the bottom left corner, sending Kuszczak the wrong way.
The Seagulls would have felt hard done by going in at half-time and Poyet wasted little time before he rung the changes; bringing on Craig Mackail-Smith and Will Buckley soon after the break to inject some pace, while Will Hoskins wasn’t far behind.
But as Albion were trying to take control of the game once again it was Kazim-Richards who had Kuszczak shuffling across his goal as he tried his luck from distance.
Poyet’s side built up masses of possession but chances were at a premium as they struggled to break down the two banks of Blackburn four protecting their goalkeeper, and in truth it was home side that came closest to doubling their lead through Rhodes.
Olsson with another delivery from the left was met by Pedersen, who headed the ball in the direction of Scotland international Rhodes; the 22-year-old’s header looked to be nestling in the top corner but Kuszczak clawed the ball away to safety with a stunning save.
Yet with five minutes of added time at the end of the game Albion were still searching for something from the game. Kean got a soft punch on Buckley’s cross, which fell straight to David and his header looped up onto the roof of the Rovers goal.
But David wasn't finished just yet and his last-gasp penalty ensured the loyal band of Albion fans left Ewood Park happy.