Joe Gallen hailed debutant Matt Casey after he helped Pompey march into the last 16 of the Checkatrade Trophy.
The first-year professional was handed his Blues bow in the victory over Arsenal under-21s at Fratton Park last night.
The academy graduate delivered encouraging performance as Kenny Jackett’s side ran out comfortable 2-1 winners.
Casey started in a centre-back role alongside Christian Burgess and rarely put a food wrong all evening.
He showed composure on the ball, while he read the play to make a number of interceptions.
The 6ft 8in defender has been out on loan at Gosport Borough this season and Gallen reckons his appearance against the Gunners will do his confidence the world of good.
Pompey’s assistant manager said: ‘Matt’s a giant isn’t he!
‘I’m pleased he’s got out there and played for us and I thought that he played well.
‘He grew in confidence and with the size of him you’re expecting him to win a lot of headers in both boxes.
‘We were expecting him to clear a lot crosses coming into the box because that’s going to be his game.
‘That will do his confidence the world of good.’