One point and one place separated these two at kick-off, and with both still looking over their shoulder in the battle to avoid the Championship trap door this season, it was clear neither were willing to give an inch.
The hosts saw an early chance slip by when Yuki Ohashi blazed over unmarked from 10 yards, and the high-and-wide effort set the tone for most of this lunchtime fixture.
Ohashi was in the thick of the action again just before the quarter-hour mark, and it took a crunching block from Ebou Adams to stop the Rovers forward getting his shot away from 12 yards.
Adams himself posed Pompey’s best threat for much of the first half at the other end, heading Marlon Pack’s flick-on just wide and then firing over after impressively muscling his way through the Blackburn midfield.
After the break, it was the hosts who had the best of the few chances created as Taylor Gardner-Hickman’s low drive slipped just the wrong side of the woodwork for before Yuri Ribeiro lashed an effort just wide.
As the game moved inside the final 10 minutes, it seemed as though this one would go down as a scrappy goalless draw, before Ogilvie popped up to rifle home a strike from the edge of the area via a slight deflection off a Blackburn defender with six minutes left.
The game’s first shot on target sparked the hosts into life for one last throw of the dice in the final five minutes, and they got their reward as former Portsmouth player Carter guided a header beyond Nicolas Schmid in the final few seconds.
While the point keeps both sides worryingly close to the bottom three, Rovers can at least celebrate being on the right side of a last-minute equaliser – having thrown away more points than any other team in the division from winning positions so far this campaign.
Pompey make the trip back to the South Coast now on a run of just one defeat in four away league games.