Pompey will find out who they will face next in the Checkatrade Trophy on Friday.
The Blues won all three of their Southern Group A matches to reach the next stage of the competition.
That perfect record means Kenny Jackett's team have made sure of a home tie in the second round.
The draw will take place in Portsmouth – at the Checkatrade.com base at Lakeside, North Harbour (1pm).
And Pompey, who beat Spurs under-21s this week, could welcome the north London side's arch-rivals, Arsenal, in the next round.
The Gunners’ youngsters finished second in Southern Group G, above Coventry City and Forest Green Rovers, but runners-up behind Cheltenham Town.
Midfielder Joe Willock, who made his Premier League debut in the Gunners’ clash at Newcastle United last season, netted twice in the 3-1 win over Forest Green on Tuesday.
Tyreece John-Jules got the other goal as Arsenal’s young guns made it through in the competition.
Another possible opponent is League One title rivals Peterborough, who are currently five points behind Jackett’s table-toppers.
The Posh finished second in Southern Group H.
Northampton sealed a spot in the second round and could also face the Blues.
The League Two side finished second in Southern Group F – a section that included Oxford United, Wycombe Wanderers and Fulham under-21s.
The Cobblers were 2-0 winners over Fulham's young guns on Tuesday.
AFC Wimbledon, Pompey's League One rivals, are the other potential opponents.
The managerless Dons ended their Southern Group G campaign with a 4-0 home success over Stevenage Town, securing second spot in the table.
All second round ties are to be played over the week of December 3.