The top two sides in division one both suffered surprise defeats.
Craneswater A were beaten by bottom side Copnor B.
However, they did contribute to their own downfall, with only five cueists on duty.
Andy Boulton beat John Shervell with ease.
Norman Bradfield then replied for Copnor against Steve Cole with a handy 49.
Pedro Ferguson gave the Southsea gang the lead.
But a spirited nine-point win by John Oldfield against Colin Rowe squared it up again.
Home skip Tony Hansford then fell to John Wyatt and the walkover gifted Copnor a welcome 5-2 victory.
Second-placed Leigh Park were surprised by Cowplain Gas and lost 6-2.
Both sides accrued 808 points and got a bonus point each.
Mark Raynor was the only home winner with a massive 92-pointer over Steve Hughes.
Home captain Neville Moyle was pipped by Mark Tillison, who managed a 37.
Mick Mo, Heath Smith, Mike Scott and Carl Fuggle won the next four pairings.
Copnor C bashed their A team 5-2 without a Dave Lawrence victory.
He suffered his first defeat as Jon Sunderland romped home 150-41.
Steve Morgan also notched a win but that was it as John Baldacchino delivered.
Portchester X beat Craneswater R 5-2.
Andy Carter shone for the visitors but Andy Macey, Lee Gaylor, Neil Turp and Charlie Cripps won for the hosts.
In division two, Topspot were thrashed 6-1 by Craneswater Z. Matt Johnson prevented the whitewash.