Joe Gallen hailed an efficient victory, as Pompey booked their place in the last 16 of the Checkatrade Trophy.
A goal in each half from Gareth Evans and Stuart O’Keefe meant the hosts comfortably saw off struggling Northampton on the south coast.
It might have been even more convincing, with former Fratton loanee David Cornell making some vital saves after the break.
But Gallen was pleased to see a united Blues side impress at both ends of the pitch against the Cobblers.
Pompey’s assistant manager said: “It was a very professional and efficient performance from us – and we’ve seen a few of those recently.
“We looked organised and capable of scoring goals, while also being pretty solid at the back to keep a clean sheet.
"It was a very professional and efficient performance from us – and we’ve seen a few of those recently."
“When you get those two things right, then you’ve usually got the making of something pretty decent.
“Northampton did have a big chance early in the second half with a header from a free-kick, but Luke made a brilliant save.
“But looking back over the full 90 minutes I felt it was a comfortable victory and one that was well deserved.
“Their keeper also made some good stops – there was a 30-second period when he made three in a row.
“The group is very spirited currently and there’s a lot of unity in the dressing room – you can see that on the pitch.
“You can have great players, but it’ll be tough if they don’t get on. You need that willingness to work hard for each other and it bodes well that we’ve got that.”
With a number of players carrying knocks, youngsters Matt Casey and Bradley Lethbridge were named on the bench.
Gallen said: “They’ve both been doing well for the youth team on Saturday mornings. When those opportunities arise, that’s what the academy is there for.”