Portsmouth head coach Neil McRoberts insists his team have the quality to upset hosts Winchester.
He knows it will be a huge scalp for his side and boost their title bid in London three south west.
McRoberts believes his third-placed side are capable of upsetting the unbeaten league leaders on their own patch on Saturday.
He said: ‘We are aiming to go up there and be the first team to lower their colours this season.
‘If any squad can do it then I believe ours can.
‘We have to carry on from our excellent performance against Battersea Ironsides.
‘If we can replicate that then we will give ourselves a chance.
‘We saw that when we keep our overall structure it allows us to execute our game in both defence and attack.
‘At the same time we need to maintain the same levels of aggression and physicality.
‘Keeping our penalty count against down to below double figures again will be an important factor.’
McRoberts knows a number of the Winchester players from his days coaching in the Hampshire County set-up.
They are a dangerous outfit and Portsmouth will have to be at their best if they are to spring a surprise.
McRoberts added: ‘Winchester have won 10 out of 10 but we won't allow ourselves to get too hung up on that.
‘We know they can be devastating in broken play.
‘Our aim will be to try to starve them of possession and opportunities.
‘It is all about players going out there and winning their personal battles.
‘If they can do that then it will give us every chance.
‘We must go out there and focus on playing our game and doing what we do well.
‘When we do that we look very good.
‘It will be fantastic if we can win the game but we must try and make sure we take something from it.’
Portsmouth are boosted by the return of two influential players, hooker Greg Hoolihan and three-quarter Sully CauCau.
The inclusion of the experienced Hoolihan allows Tim Snowden to move into the back-row.
Also in London two south west second-placed United Services Portsmouth face a tricky assignment at Battersea Ironsides.
Petersfield host Warlingham at Penns Place.