The Blues were badly running out of ideas, with Abu Kamara the chief culprit towards the end, as the match threatened to peter out for a frustrating goalless draw.
But Kamara was brought down and unpopular referee Craig Hicks pointed to the spot for Bishop to net – and here are our Pompey player ratings...
13. Jack Sparkes
(Replaced Connor Ogilvie on 61 mins) Photo: Jason Brown
14. Josh Martin
(Replaced Paddy Lane on 82 mins) Photo: Jason Brown
15. Ryley Towler
(Replaced Colby Bishop on 90 mins) Photo: Jason Brown
16. Portsmouth forward Paddy Lane (32) during the EFL Sky Bet League 1 match between Port Vale and Portsmouth at Vale Park, Burslem, England on 27 January 2024.
Pompey's Paddy Lane looks to threaten against Port Vale. Picture: Jason Brown/ProSportsImages Photo: Jason Brown