Conor Chaplin grabbed a hat-trick as Pompey Reserves thrashed Exeter 6-2 in the Central League Cup group stages.
The victory in Devon saw the Blues leapfrog their opponents into second spot and qualify for the semi-finals.
Jamal Lowe opened the scoring with his first goal in a Pompey shirt, reacting quickest to fire home after skipper Ben Close’s shot had been parried clear.
Matt Jay levelled for the Grecians at their Cliff Hill training base, only for Adam Buxton to convert a free-kick from the edge of the box.
Pierce Sweeney struck to equalise for Exeter after the interval, but the Blues then tore their hosts apart with a display of clinical finishing.
Amine Linganzi restored Pompey’s advantage with a long-range effort that arrowed into the bottom corner of the net.
And Chaplin then took charge, first jinking his way into the box before calmly lifting the ball over Bobby Olejnik and into the net.
Exeter’s keeper then took too long to get the ball clear and was dispossessed by the Blues’ diminutive forward, who slotted into an empty net.
Chaplin completed his treble from the penalty spot in the closing stages after Buxton was brought down in the box.
Coach Mikey Harris said: “It was a timely game for us, seeing as the first team were not in action over the weekend.
“There was an opportunity for some of our players to get important minutes under their belts, while the younger guys were able to integrate with the older professionals.
“We produced an encouraging performance with some nice goals in an all-round good game of football – something you’ll always get when you face Exeter.”
Exeter: Olejnik, Sweeney, Archibald-Henville (Down 59), Storey, Croll, Tillson, Ampadu, Byrne, Riley-Lowe, Jay (c), Simpson
Subs not used: Egan, McCready, Collins, Seymour
Pompey: O’Brien; Buxton, T.Davies, Whatmough, Talbot; Linganzi, Close (c) (Haunstrup 67); Lowe, Bedford (Bradbury 67), Lalkovic (Widdrington 70); Chaplin
Subs not used: Hall, Collins
Referee: Devon Campbell