Portsmouth opened up their London two south-west campaign with a 32-26 defeat at Warlingham.
The Rugby Camp club came away with two bonus points but director of rugby Nigel Morgan felt they could easily have won.
Some mistakes from the visitors proved costly at key times.
Those errors stopped Portsmouth from taking the match by the scruff of the neck.
‘It was a decent game and it could have gone either way,’ said Morgan.
‘We were guilty of making mistakes which kept letting them back into the game.
‘Our forwards did really well with our scrum and line-out both going well.
‘Loose-head prop Ben Cuming was probably the pick of our players.’
Portsmouth led in the first half 14-12.
Two tries from Curtis Barnes were both converted by Simon Morgan as the visitors powered forward.
But the home side fought back to take command of the match.
Then a try from Luke Simmons, converted by Morgan, on the hour brought them within a point of the hosts at 22-21.
Warlingham then stretched their lead with a penalty and converted try.
Damien Gibbs made sure of the second bonus point for the Rugby Camp club with a last-minute try.
‘Considering Warlingham finished fourth last season and were unbeaten at home this isn’t a bad result,’ said Morgan.
Newly-promoted United Services celebrated a winning start in London three south-west with a 32-27 success at Old Tiffinians.
Petersfield made a disappointing start to their Hampshire one campaign with a heavy 55-7 reverse at Sandown & Shanklin.
Southsea Nomads gave new coach Jamie Clayson a winning start in Hampshire two by beating Kingsclere 36-10 at Furze Lane.
Clayson was proud of the way his team performed in their bonus-point win.
‘The lads were buzzing for this game and it showed in the final scoreline,’ said Clayson.
‘We worked hard as a cohesive unit and showed robust defence when we needed it.
‘In attack we had plenty of options and the players showed just how far they have come in a short space of time.’
Lukas We, Ross Edwards, England Deaf international Aaron Beesley and Alex Kasoke scored tries with Jonathon Branston adding a penalty and three conversions.