Greg Houlihan was sent off as Portsmouth crashed to a 49-10 defeat at London two south west leaders Chobham.
The hooker received his red card for over-zealous rucking late in the game as the Rugby Camp outfit’s promotion ambitions were left hanging by a thread.
‘The odds are lengthening on promotion,’ said head coach Ian Chandler.
‘We will now have to win all our remaining games.
‘You can’t expect to get a result when you visit the top side without 11 of your first-team squad.
‘It was always going to be a difficult day but I can’t fault the effort of the players who came in.’
Portsmouth found themselves 18-0 down after 25 minutes as the reshuffled side searched for some cohesion.
In their best spell of the game, Houlihan grabbed a try 10 minutes before half-time following good work from Steve Gee on the blindside.
The home side soon regained control, though.
They established a 23-5 lead before pulling away in the closing stages when Houlihan’s dismissal – and a yellow card for Lee Chandler – reduced the visitors to 13 men.
Prop forward Dan Sargent kept his remarkable scoring run going, however, as he notched his 19th of the season in the final minutes.
United Services suffered a third successive Hampshire one defeat as they went down 19-11 against leaders New Milton & District.
‘This is a young team with a great future ahead of them,’ said head coach Simon Burns.
‘We have had five tough games, all of which have been close.
‘The average age of our front row is only 20 years and all the players have risen to the challenge.’
New Milton scored an early try before Services hit back with a penalty.
But when the visitors lost Will Blackett – needing seven stitches in his finger – the home side took advantage to lead 19-3 at the break.
Services grabbed the only points of the second half through an Alex Doolan try and a drop goal from debut-making Kit Wapshott.
Petersfield lost 31-12 at Aldershot & Fleet and a depleted Fareham Heathens crashed to a 36-12 Hampshire two defeat at Chineham.