The hosts lost Jordan Rhodes just before half-time following an aerial challenge on Joe Rafferty, with the red card looking a tough soft.
The Blues subsequently hit the post three times, yet that masks a fitful performance from John Mousinho’s men who failed to press home their numerical advantage.
A goalless draw means Pompey’s lead at the top of League One is cut to five points – and here are our player ratings...
5. Jack Sparkes - 6
(Replaced by Kusini Yengi on 74 mins) His first start since mid-January and understandably a little rusty. Couldn’t get a rapport with Lane down the left and his corner delivery was disappointing. Had a decent second-half free kick saved by Grimshaw. Photo: Jason Brown
6. Marlon Pack - 7
Tried to be a calm presence, particularly during some testing moments in the first half when his team needed to keep possession. Yet couldn’t inspire a below-par Blues. Photo: Jason Brown
7. Myles Peart-Harris - 5
(Replaced by Owen Moxon on 46 mins) - Retained his place in the centre of midfield, yet frustratingly couldn’t impose himself during the first half. Yet to convince it’s his most effective position. Collected a first-half booking. Photo: Jason Brown
8. Paddy Lane - 6
Struggled to get a connection with Sparkes on the left, perhaps understandable considering lack of recent action together. A couple of decent runs but little of any consequence. Dropped into left-back area once Sparkes went off. Photo: Jason Brown