Assistant coach Jim Pearce is worried that losing can become a bad habit.
In the games played so far, Portsmouth have got themselves into good positions only to fade.
Pearce knows if they are to turn their fortunes around they will need to play better for longer.
‘I am sure that all we need do is get a first win under our belt,’ said Pearce.
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‘We have been in the ascendancy for the first 25 minutes in games and then dropped off.
‘It is important that when we do get a lead we keep pressurising and put our chances away.
‘We were in exactly the same position last season when we lost our first three games.
‘Last year we turned it around and must look to do the same again.’
Portsmouth are boosted by the return of some experienced and influential players.
Tight-head prop forward Ryan Wilkie is back from injury and he is joined in the front row by Sam Cutting.
Also in the forwards Darren Crabbe and Greg Hoolihan return from wedding duties, allowing Rhys Bowen to move to number eight.
In the three-quarters Sam Ellis is back from university to take his place on the wing.
On the other wing Dan Gates is back from injury.
Gareth Richards moves to inside centre in place of the unavailable Lee Chandler.
United Services Portsmouth are keen to bounce back to winning ways in London three south west at Teddington (3pm).
Services slipped to a surprise loss against Trojans who scored seven tries.
‘We suffered a bad day at the office,’ said director of rugby Matt Davis.
‘They caught us napping a few times and we paid the price for lapses in concentration.
Southsea Nomads entertain Lymington Mariners at Furze Lane (3pm) keen to carry on where they left off in their thumping win at Kingsclere.
‘It sets us up nicely for the campaign ahead,’ said Nomads captain Ben Horrod.