The recent recruit from Hampton & Richmond netted in the reserves’ 4-0 hammering of Norwich under-23s on Monday night.
It took only 14 minutes into his maiden Blues start at any level to register, turning home Jamal Lowe’s pass.
Cook was among the 281 crowd gathered at Westleigh Park for the Premier League Cup fixture, in which Lowe helped himself to a hat-trick.
And he was impressed with a player he insists is under first-team consideration this season.
‘If you look at the game, would you notice those were new boys? No. That is the biggest compliment you can say,’ said Cook.
‘Of course Kabamba is under first-team consideration, without a doubt.
‘If you are looking at a run-in and we bring a lad in for a small amount of money it doesn’t really satisfy people.
‘We are actually in the market to satisfy our fans, but we have also brought in a lad we believe could have an impact on the run-in. Let’s see.
‘I put Jamal Lowe on at half-time in the last game (Orient), so I wouldn’t have any fear about putting any player within our squad on the pitch now, not at all.
‘They are both smashing players and there are loads of lads that have come through non-league.
‘The lad Scotty Hogan at Brentford has been spoken about as a £10-15m player, yet not so long ago played for Stocksbridge Park Steels, so these lads are out there.
‘Sometimes it’s about clubs giving them the opportunity. It’s not about where they have been but where they can go.
‘There is always an element of looking to next season, but lads will get an opportunity.
‘Kabamba scores a goal Monday night, looks good, looks strong and is athletic, so all of a sudden anyone can force their way into a manager’s plans.
‘We have plans for every player. The player can change that by what they do on the pitch, of course they can.
‘The pair of them are doing okay, doing smashing, they have slotted in very, very well.’
Lowe can expect to retain his place on Pompey’s bench for the visit of Exeter, following his half-time appearance against Orient.
The forward replaced the injured Gareth Evans to mark his Blues debut.
Kabamba, though, may find it tough to dislodge striking rival Noel Hunt from the bench.