A slow start proved costly for Portsmouth as they lost 27-7 to KCS Old Boys in London Two south west at Rugby Camp.
Will Phillips got the home side’s only try, with Bobby Owen kicking the conversion.
Portsmouth coach Ian Chandler feels his young side must improve.
‘We have to learn to play for 80 minutes,’ he said.
‘If we had started the game like we finished it then we could even have won it.
‘But we are still a very young side learning to play at this level.’
Chris Marriott grabbed a hat-trick of tries as United Services crushed Alton 69-0 at Burnaby Road.
The win moved unbeaten Services to within a point of leaders Bognor at the top of Hampshire one.
‘Though we led 28-0 at half-time, the first half had been a bit flat,’ said Services coach Graeme Butterworth.
‘In the second half we established our patterns, with our outside-half Tom Blewitt orchestrating matters.
‘Kelvin Roberts showed what an aggressive runner he can be and all our three-quarters attacked at pace.
Roberts, Sam Porter, William Rolfe, Ben Smith and Martin Hoskins, twice, all crossed for tries.
Fareham Heathens recorded a 17-8 win over Romsey at Cams Alders.
Johnny Stoppard, Ollie Whitfield and Steve Devoy scored tries for Heathens.
Cam Guthrie kicked one conversion but Heathens did not get a bonus point from the victory.
Coach Bernie Rhodes said: ‘We were not able to secure enough quality ball to achieve it.’
Petersfield recorded a bonus-point win, beating Isle of Wight 29-18.