John Mousinho’s men trailed 3-0 at the interval and never looked like finding a way back into the match, despite a system switch and using three substitutes.
Orient were comfortably the superior side and that is now five points from six matches – and here are our Pompey player ratings...
13. Tom Lowery - 6 - MOM
(Replaced Christian Saydee on 46 mins) Back after injured since August and it was damning on his team-mates that he was comfortably the best performer. Showed energy and imagination glaringly missing and only bright spot. Photo: Jason Brown
14. Terry Devlin - 4
(Replaced Jack Sparkes on 46 mins) Frustratingly failed to make any impact, despite customary effort. Overshadowed by fellow substitute Lowery. Photo: Jason Brown
16. Portsmouth forward Christian Saydee (15) during the EFL Sky Bet League 1 match between Portsmouth and Leyton Orient at Fratton Park, Portsmouth, England on 13 January 2024.
Pompey's Christian Saydee attempts to keep possession against Leyton Orient. Picture: Jason Brown/ProSportsImages Photo: Jason Brown