Top men's player Matt Spooner held the fort for Carterton, winning both of his matches in straight sets but it was all in vain as Opaki were clearly the better team on the night.
Gladstone overcame the late withdrawal of leading man Kelby Courtney to see off the challenge of Martinborough 4-2.
Played at the neutral venue of Carterton, the Gladstone men stepped up to the plate after they were all moved up the order due to Courtney's absence.
Alistair McWilliam fronted the Gladstone charge and his three-set victory over Andy Darling in the top men's singles was particularly noteworthy.
His performance was backed up by Scott Day, who kept his clean sheet for the season intact with a solid win over Bruce Lovell, and Lochie McNab who made a triumphant step up to the regional one level for Gladstone.
As she so often does, Rhona Lovell kept the southerners in the hunt with a quick-fire singles victory and she also combined with Darling to claim her second win for the evening. However, McWilliam and McNab were able to seal the deal for Gladstone with a doubles victory to complete a top evening for both of those players.
Heading into the Christmas break Carterton are on top of the ladder, though Gladstone have closed within 2 points while Opaki has pulled up level with Martinborough into third equal position. Masterton are fifth but do have a match in hand.
Scores: Opaki beat Carterton 4-2 (Opaki names first). - Men's singles: Chris Davidson lost to Matt Spooner 1-6 2-6; Stuart Wyeth beat Hideki Tadamasa 1-6 6-0 6-2; Jon McNab beat Ross Collings 6-1 6-3. Women's singles: Katie Alsop beat Kirsten Tatham 6-0 6-1. Men's doubles: Wyeth and McNab lost to Spooner and Collings 2-6 4-6. Mixed doubles: Davidson and Alsop beat Tadamasa and Tatham 7-5 6-0.
Gladstone beat Martinborough 4-2 (Gladstone names first). - Men's singles: Alistair McWilliam beat Andy Darling 4-6 6-3 7-6; Scott Day beat Bruce Lovell 6-2 6-1; Lochie McNab beat Tim Martin 6-1 6-1. Women's singles: Becca Perry lost to Rhona Lovell 1-6 1-6. Men's doubles: McWilliam and McNab beat Lovell and Martin 6-2 6-0. Mixed doubles: Day and Percy lost to Darling and Lovell 4-6 7-6 6-7.d
Points: Carterton 30, Gladstone 28, Martinborough 14, Opaki 14, Masterton 10.