In a match when neither keeper had much to do, particularly the visitors, Romain Esse’s 13th-minute goal was enough to earn Millwall victory.
Pompey raised their game in the second half, with Sammy Silvera and Zak Swanson catching the eye, yet they couldn't carve out enough opportunities to force home an equaliser.
And here are our Pompey player ratings...

9. Sammy Silvera - 8
(Replaced by Paddy Lane on 76 mins) Operated on the left of the attacking three and the brightest of them all. Some good moments and glimpses of skill. Definitely has something about him and possesses a real spark at times. Photo: Jason Brown

10. Gavin Whyte - 6
(Replaced by Matt Ritchie on 64 mins) - Familiar story at Pompey, plenty of effort yet nothing quite comes off for him in an attacking sense and struggles to impact games consistently. Put in a couple of testing crosses in the second half during a good Pompey team spell. Photo: Jason Brown

11. Christian Saydee - 7
(Replaced by Callum Lang on 76 mins) Lined-up at centre-forward and never gave the Millwall defence a moment’s peace. Chased, harried, and at times impossible to knock off the ball. Barely had a goal-scoring opportunity, though - 7 Photo: Jason Brown

12. Portsmouth Sammy Silvera (20) during the EFL Cup match between Portsmouth and Millwall at Fratton Park, Portsmouth, England on 13 August 2024.
Sammy Silvera on the attack for Pompey in their Carabao Cup clash with Millwall. Picture: Jason Brown/ProSportsImages Photo: Jason Brown