Pompey exited the Carabao Cup with a narrow defeat to Championship side Millwall at The Den.
Danny Cowley's side made a fast start and broke the deadlock through an impressive strike from Reeco Hackett-Fairchild.
Scott Malone and George Saville both scored for the home side before the break, however, and Callum Johnson's controversial dismissal helped them hold on for a 2-1 win.