There was a sense of déjà vu for Pompey at the Memorial Stadium.
For the second Saturday in a row, they conceded from a set-piece deep into stoppage-time that proved costly.
A free-kick ultimately led to an undeserved defeat at AFC Wimbledon seven days ago, while it was a corner that undid them at Bristol Rovers.
Liam Sercombe’s delivery struck Ross McCrorie, the crossbar and Craig MacGillivray before crossing the line to rescue a point for the hosts.
Pompey looked to have done enough to secure the win through Gareth Evans’ early penalty and a Ronan Curtis header before Alex Rodman and that late own-goal ensured a cruel conclusion.
And Kenny Jackett knows his side have to deal with balls into the box better if they are to find some more consistent form.
The Blues boss said: “We’d got ourselves into a very good position and were ahead at the break – we could have had more and their keeper made some great saves.
“They put us under a lot of pressure at the start of the second half, but it did seem as though we’d come through it.
"You always know that you need to see it out, but that’s two Saturdays in a row where late set-pieces have directly cost us."
“We were playing really and got the second goal through John’s cross for Ronan, but then we conceded from two set-pieces.
“Rodman’s got the first and then it’s obviously gone in off our own player right at the end, with the ball finding its way into the net.
“You always know that you need to see it out, but that’s two Saturdays in a row where late set-pieces have directly cost us.
“We’ve got one point out of six from those situations and have to improve to be able to kill those games off.
“You can try to give away fewer free-kicks, although I do want my players to compete, and we have to keep working to eradicate those instances.
“There are times when you go away from home and are happy with a draw, but this isn’t one of them because we looked in control.”
Curtis impressed on his recall to the starting line-up, while Jackett was also pleased with Ryan Williams on the opposite flank.
He said: “We had real threat on both wings and I was really pleased with that, while Marcus Harness has to draw breath and be ready to go again.
“There are three places behind the striker and Gareth produced another good performance, taking his penalty well.
“It hasn’t done Ronan any harm to have a few games out of the side and hopefully his goal can signal the start of a positive run of form.”