The Blues progressed to the second round of the competition following Sean Raggett’s controversial winner for the visitors in extra-time.
The centre-back looked in an offside position when he tapped the ball across the line on 111 minutes.
Pompey raced into a 2-0 lead through goals from Ronan Curtis (11 minutes) and Tom Naylor (13).
The Tractor Boys fought back through Jon Nolan (43) and James Norwood (66) – but it’s Pompey who are in the hat for the next round thanks to Raggett’s intervention.
9. Ronan Curtis - 7
(replaced by Ellis Harrison on 74 minutes): Hungry and threatening before second-half substitution. Photo: JPIMedia
10. Ryan Williams - 8
Rampant first half and important contribution in extra-time. Photo: JPIMedia
11. John Marquis - 6
(replaced by Bryn Morris on 90 minutes): Linked up well but not his day. Photo: JPIMedia
12. Ben Close - 5
(replaced Andy Cannon on 23 minutes): Struggled against second-half tide and will want to forget big miss. Photo: JPIMedia