Ngamatapouri's speedy league convert Emitai Logadraudrau dotted down, as did Te Rau Wirihana for his second try of the season while adding a conversion and penalty.
After their upset of Kaierau last weekend, Marist secured their first back-to-back victories since 2019 by coming from behind to slip past Ruapehu 17-13 on an absolute mud heap at Spriggens Park.
Held on Ladies Day for Marist RFC, by the time the feature game got underway, the players' jerseys became so caked in mud that the opposing forwards were unidentifiable.
Ruapehu led 8-0 at halftime through an opening penalty by fullback Tuhirangi Akapita and a try out wide by winger Ben Waiwai.
But despite the wet and the muck, Marist showed the character which has marked this last fortnight, as player-of-the-day centre Jo Bogileka and winger Ioane Hough traded tries with Waiwai, who got his double.
At 13-12 to Ruapehu, it was Marist's young first five Rangi Kui who was again the hero - breaking through to score under the posts for the match-winning try, which he converted.
Fighting to make their first semifinal since 2017, Marist dealt a blow to Ruapehu's desire to keep their 13-season playoff streak alive, but it is game on for all in these last two weeks.
In Tasman Tanning Senior, Kelso Hunterville emerged with the first on-field victory over Harvey Round Motors Ratana in 20 games, hanging on 15-10.
In rainy conditions, Hunterville scored two tries to one reply in the corner from an attacking scrum, leading 12-5 at halftime.
Another corner try to Ratana closed the gap to two points, but Hunterville added a penalty and hung on to go well clear on top of the table and guarantee a home semifinal.
The biggest boilover was back at Memorial Park as Speirs Food Marton produced a 29-19 upset against Utiku Old Boys, to become the third owner of the Stihl Shop Wanganui Challenge Shield in as many weeks.
Marton showed great ball-handling skills in muddy conditions to run in several tries for a comfortable 29-5 lead and, although Utiku finished strongly, dominating the last 10 minutes, they left it too late.
The loss ended Utiku's playoff hopes, while two other sides kept themselves in the chase for one more week, but will need other results to go their way.
Black Bull Liquor Pirates stopped a clean sweep of Ladies Day for Marist by beating the Buffalos 26-7 on the Racecourse ground, while Bennett's Taihape held off Ruapehu 31-26 at Rochfort Park.
Ali Arc Logistics-DNA Kennel Marist Celtic won the derby with Gemini Pepper Construction Kaierau 19-5, leapfrogging them into third.
McCrea Scanning Counties are now well clear of the wooden spoon after a 39-3 win over Border at McNab Domain.
Results, June 19
Tasman Tanning Premier, Week 8
Dave Hoskin Carriers Marist 17 (Jo Bogileka, Ioane Hough, Rangi Kui tries; Kui con) bt McCarthy Transport Ruapehu 13 (Ben Waiwai 2 tries; Tuhirangi Akapita pen). HT: 8-0 Ruapehu.
Settlers Honey Ngamatapouri 17 (Terau Wirihana, Emitai Logadraudrau tries; Brook Tremayne con, Wirihana con, pen) bt Wanganui Car Centre Kaierau 12 (Joe Edwards, Cameron Davies tries; Davies con). HT: 12-10 Kaierau.
Grand Hotel Challenge Shield – Byford's Readimix Taihape 28 (Cyrus Paringatai, Peter-Travis Hay-Horton, Dylan Gallien, Tiari Mumby tries; Dane Whale 4 con) bt Waverley Harvesting Border 17 (Semi Vodesese, Jack Hodges tries; Nick Harding pen, 2 con). HT: 21-10.
Senior Championship, Week 9
At Spriggens Park: Ali Arc Logistics-DNA Kennel Marist Celtic bt Gemini Pepper Construction Kaierau 19-5. HT: 0-0
At Racecourse: Black Bull Liquor Pirates bt Marist Buffalos 26-7. HT: 19-7.
At McNab Domain: McCrea Scanning Counties bt Border 39-3. HT: 22-3.
At Ratana Pa: Kelso Hunterville bt Harvey Round Motors Ratana 15-10. HT: 12-5.
At Memorial Park - Stihl Shop Wanganui Challenge Shield: Speirs Food Marton bt Utiku OB 29-19. HT: 15-0.
At Rochfort Park: Bennett's Taihape bt Ruapehu 31-26. HT: 12-7.
Around the grounds
METRO: St Johns Whanganui Metro continue to deal out body-blows to the playoff hopes of MRU Colts teams after a 51-7 win over fifth-placed Massey RFC at the university grounds on Saturday. Metro keep their seven-point lead on top of the table and could guarantee it stays theirs with a game to spare if they beat Old Boys Marist away this coming weekend.
COLLEGIATE: Whanganui Collegiate 1st XV sit third on the CNI table after another midweek sports exchange victory, beating Lindisfarne College 21-15 at the school grounds. Unbeaten St Peter's Cambridge lead the table, followed by their 2020 co-champions St Paul's Collegiate.
SCHOOLBOYS: The Whanganui High School and City College 1st XVs occupy first and second on the MRU Premier 2 points ladder after victories on Saturday. WHS beat Feilding High 2nd XV 29-0 at home, while City College defeated Palmerston North Boys High 3rd XV 41-22 at Coronation Park.
SCHOOLGIRLS: Cullinane College 1st XV rebounded from their loss to beat Tai Wananga Tu Toa 46-15 at Ongley Park on Wednesday, moving into fourth on the Premier points table. Whanganui High 1st XV lost to third-place Feilding High Blue 50-17.