The under-18 manager saw Bradley Tarbuck’s double on his 17th birthday earn the Blues a third straight victory in the group phase of the competition.
But while Pompey have been free-scoring this season, Hardyman and Academy boss Andy Awford have worked on defending with the players to make them harder to break down and to broaden their footballing education.
Hardyman explained: ‘We’ve worked a lot on the attacking side of the game and some of the results at the start of the season were very entertaining, high-scoring games.
‘But while we were good going forward, we needed to work on the defensive side and, to be fair to the lads, they have really taken it on board.
'Is proving one hell of a signing.... A real livewire' - Portsmouth match ratings from 2-0 win at Cheltenham
Portsmouth boss Danny Cowley hails squad depth as tactical masterclass at Cheltenham pays off
Portsmouth loan strategy revealed following duo's arrival from Ipswich and Blackpool respectively
RECAP as Colby Bishop steal show as Portsmouth edge Cheltenham at sun-soaked Whaddon Road
‘For the sake of 90 minutes football, it’s not worth a player being off work for a year or ending up in a wheelchair’ – Hampshire grassroots football clubs postpone matches due to the heatwave
‘We have conceded only one goal in the past four games now.
‘We’re really pleased. I played under John Ward at Bristol Rovers and he was very keen on doing defensive work.
‘He almost made it into a competition and we were so solid that we were so hard to beat.
‘We are trying to get that into the lads here as well.’
While Tarbuck – who is remarkably not nicknamed Jimmy – was top of the bill, Pompey had to adapt their game to suit a poor playing surface.
Hardyman said: ‘It was probably one of the worst pitches I have ever seen an Academy game played on so we had to change our style to suit the pitch.
‘It meant we had to go a bit more direct and it took the lads time to get used to that but then we played some good football.
‘Bradley scored two, should have had a hat-trick and it was all on his 17th birthday.
‘His best position is probably out wide right, but he played in just off the main striker and he took to it quite well.
‘He asked if he could play there, which is good that he has the confidence to come to the coaches to do that.
‘He’s done very well in several different positions this season.’
Pompey’s new defensive steel could face a major challenge in the third round of the FA Youth Cup at Bolton, if they can get past Woking next Tuesday at Fratton Park (7.30pm).
Hardyman said: ‘We’ve got Bolton in the next round of the FA Youth Cup if we can beat Woking.
‘They are flying. They beat Arsenal 5-1 earlier this season and a few people up there are saying it is their best ever youth team, so they must be half-decent.
‘That will be a massive test if we can get through the second round.’