Moneyfields surrendered top spot in the Wessex League premier division after a disappointing 3-2 defeat at the hands of Bemerton Heath Harlequins at Dover Road.
The Copnor club clawed their way back from a two-goal deficit only to concede a late winner to the visitors.
Manager Dave Carter blamed sloppy defending for the setback.
‘Schoolboy defending cost us in the end,’ he said.
‘That is five points dropped in the last week in two games we could easily have won.
‘We are badly hit by injuries at the moment and only had two fit players on our bench.
‘I am looking to bring four players in this week to boost the squad.’
Moneyfields squandered a series of good chances before falling behind in the 15th minute.
Carter’s team started the second half well only to fall further behind around the hour mark.
Nathan Paxton got the hosts back into the game when he capitalised on a goalkeeping error to pull a goal back.
Soon afterwards, he was brought down in the area and Steve Hutchings levelled from the spot.
Then Moneyfields paid the price for not playing to the whistle 10 minutes from the end.
A long ball over the top left the home defenders waiting for an offside flag that never came and Bemerton snatched the winner.
‘To be fair, our back four were dead on their feet and it is good we now have a week’s rest,’ said Carter
Elsewhere, 10-man AFC Portchester came from behind to secure a 2-1 win over Amesbury Town at the Blanchard Wells Stadium.
The Royals had Josh Warren sent off in the opening 15 seconds
In a spirited response, however, goals from Jake Peppel and Dale Mason earned the hosts an unlikely win.
‘It is a fantastic result after playing so long with 10 men,’ said Royals boss Graham Rix.
‘I was proud of the way my players stuck to their guns with a terrific work-rate.’
A Benny Reid brace earned Horndean a deserved 2-1 win over Lymington Town at Five Heads Park.
Reid struck in each half before the visitors pulled a goal back with 15 minutes remaining.
Michael Birmingham felt his team saw the game out well.
‘We were sharp out of the blocks, dominated but again failed to take chances,’ said the boss.
‘After they scored I felt we managed the game well.’
Fareham Town and Bashley fought out a 0-0 draw at Cams Alders.
Reds boss Steve Stone felt the draw was a fair result.
‘For a game without any goals it was quite entertaining,’ he said.
‘Our goalkeeper, Tom Boyle, made some good saves in the first half and Simon Woods could have sneaked it for us towards the end.
‘With just 12 fit players, I am happy to come away with a point.’
Fareham play United Services in the Portsmouth Senior Cup at Burnaby Road tonight (7.45pm).