Injury-ravaged Portsmouth produced a much-improved performance but went down 37-10 at fourth-placed Old Elthamians in London one south.
The visitors were still in contention, trailing 16-10 going into the final 15 minutes, but were badly disrupted by the loss of Jason Crabb and Adam Long to injury.
As a result, the home side exploited Portsmouth’s need to reshuffle and plundered three late tries.
‘For 65 minutes, we did really well,’ said Portsmouth coach Ian Chandler.
‘Crabb and Long had been dominating the loose play before they had to go off and we were putting Old Elthamians under a lot of pressure.
‘We tired towards the end and finished with two teenagers in our second row.’
The start to the game was delayed for 45 minutes after the referee arrived late following a car accident.
When the contest eventually started, Portsmouth found themselves playing up the slope and into the sun.
Good defence saw them reach half-time only eight points adrift and they soon reduced the arrears right at the start of the second period.
The platform was provided by a good scrummage and, after four phases of play, Sandy Duffus went over for a try which was converted by Andy Barnes.
The two sides swapped penalties before the home side grabbed another try against the run of play.
Portsmouth fancied their chances of winning but the double-injury blow struck.
‘At the moment we have a whole pack of forwards missing due to injury or unavailabilty,’ said Chandler.
‘If we play like we did for the opening 65 minutes we will have nothing to worry about and the players to come back will make us stronger.’
Portsmouth II 10 Gosport XV 28;
Portsmouth III 10 United Services XV 34;
Portsmouth IV 15 Petersfield XV 10