It was a defensive display that was the stuff of nightmares for the Fratton faithful.
Pompey showed plenty of attacking flair against Coventry, only to end up drawing 3-3 with their nine-man opponents.
Goals from Ronan Curtis, John Marquis and Gareth Evans saw them recover from falling behind to Jordy Hiwula’s strike.
Fankaty Dabo and Gervane Kastaneer were then sent off for the visitors, either side of Matt Godden netting from the spot.
And Michael Rose completed a remarkable City comeback that left Kenny Jackett questioning his side’s generous defending.
The Blues boss said: “There’s obviously disappointment and frustration because we were in a winning position and basically threw two points away.
“You look at the goals and Lee Brown stepped up for the first one. I was in line and it certainly didn’t look offside.
"It’s two big points that we’ve lost and of course we know that we have to be better defensively as a unit."
“Then Ben Close has given a needless penalty away for the second when their lad was not going anywhere.
“The third came from a long throw into our box and I think they had two players against our five. We had enough people to win the first ball.
“It was a reflection of the game for us if I’m being truthful. We looked a good side going forward, but were shaky throughout defensively.
“That’s a little bit of the opposite of what happened last season and we haven’t quite got it right at the back.
“It’s two big points that we’ve lost and of course we know that we have to be better defensively as a unit.”
Pompey are also now sweating on the fitness of left-back Brown, who limped off the pitch during the first half.
Jackett said: “He felt his Achilles quite badly – I think it was a contact injury. We don’t know the extent of it yet and hopefully he’ll be okay.
“Brandon Haunstrup was okay coming in. He’s waited for his chance and will get his opportunity now if Lee is out.”