Portsmouth paid for two spells of ‘complete madness’ as they lost 41-19 to Weybridge Vandals at Rugby Camp.
The home side dominated much of the London two south west contest, only to throw the points away.
Portsmouth coach Ian Chandler was left shocked after seeing his team implode.
He said: ‘It was unbelievable. We had two spells of complete madness, one in each half, which made the scoreline totally unrealistic.
‘In those 12 minutes Weybridge scored five tries, adding over 30 points to their tally.
‘It was all down to individual errors and poor decision-making at times.
‘You cannot do that and expect to win games.’
Portsmouth came into the match looking to end a run of three straight league defeats.
They started confidently, camped in the opposition half, and raced into a 14-0 lead.
Tries came from outside-half Chris Morgan and winger Mark Ovens.
Morgan converted both, as Portsmouth looked in good shape.
However, things started to go wrong before the break with Portsmouth failing to push their advantage home.
‘We lost our composure and panicked when we had two other great chances to score,’ said Chandler.
‘Then we had a player yellow-carded and started to give a series of penalties away.
‘Weybridge made us pay by scoring two catch-and-drive line-out tries.
‘I couldn’t believe we were only leading by two points at the break.’
Early in the second half, Portsmouth went down to 14 players again.
This time the yellow card proved very costly.
When an attempt to run a ball clear of danger broke down, Portsmouth were caught out and found themselves behind 19-14.
They then had to push forward but that led to a flurry of tries from the visitors.
Chandler said: ‘We were chasing the game and shipped three more tries in seven minutes.’
Home winger Ovens grabbed his second try – the best of the game – in the final stages but it was little consolation for the hosts.
‘It is a tough lesson for some of our young players to learn,’said Chandler.
‘Three of our forwards – Greg Hoolihan, Adam Long and Jackson Clark – were immense and didn’t deserve to be on the losing side.
‘They were the three best players on the pitch by a country mile.
‘Our defeats are not down to a lack of effort.
‘It is more about knowing when and where to play the game.’
The defeat leaves Portsmouth third from bottom.
But Chandler is in positive mood, knowing that he has a number of experienced players to come back.
He said: ‘We know where we are but feel we have the resources in the club to deal with it.
‘We can’t keep conceding the number of points that we are and expect to win.’