The Hanan Shield districts now have three of the top four places in the competition with South Canterbury on top with 30 points, two clear of Thames Valley.
However, it took a golden point penalty goal for Mid Canterbury goal-kicker Tom Reekie to break the 19-19 fulltime deadlock in Ashburton.
But it was worthwhile as the win lifted Mid Canterbury into a share of third place.
Whanganui lost its solitary claim to the position when going down to competition pace-setter South Canterbury 14-28 in Timaru. It now has a share of 20 points with Mid Canterbury and North Otago who scored a bonus points 45-29 win over Buller in Westport.
Horowhenua Kapiti lost to second-placed Thames Valley 11-28 and slipped to sixth position with Poverty Bay back to seventh after the Mid Canterbury result.
Bunnings Heartland Scores:
Buller 29 North Otago 45
Buller 29 (Mitieli Kaloudigibeci 3, Erenimo Tau tries; Jesse Pitman Joass 3 con, pen) North Otago 45 (Levi Emery 2, Tony Taufa 2, Sam Sturgess, Ralph Darling, Aesesia Ravuvu tries; Able Magaloa 5 con). HT: 3-33
West Coast 39 East Coast 34
West Coast 39 (Jacob Lowe, Sam Liebezeit, Steve Soper, Anthony Tailua, Joseph Scott tries; Sean McClure 4 con, 2 pen) East Coast 34 (Gabe Te Kani, Willie Bolingford, Teina Potae, Te Rangi Fraser, Te Wehi Wright tries; T Fraser 3 con, pen). HT: 22-22
Horowhenua Kapiti 11 Thames Valley 28
Horowhenua Kapiti 11 (Darren Falaniko try; Jack Tatu-Robertson 2 pen) Thames Valley 28 (Sam van der Valk, Todd Doolan, Cameron Dromgood tries; Doolan 2 con, 2 pen; Telly Hemopo pen ). HT: 6-13
King Country 12 Wairarapa Bush 24
King Country 12 (Joe Curuki, Kody McGovern tries: John Ika con) Wairarapa Bush 24 (Lewis Bush 2, Soli Malatai 2 tries; Tipene Haira 2 con). HT:
Mid Canterbury 22 Poverty Bay 19
Mid Canterbury 22 (Manasa Bari, Callum Burrell, Seta Koroitamana tries; Tom Reekie 2 con, pen) Poverty Bay 19 (Shayde Skudder, Ethine Reeves, Keanu Taumata tries; Jake Holmes 2 con). HT: 12-5. FT: 19-19
South Canterbury 28 Whanganui 14
South Canterbury 28 (Sireli Buliruarua 3, Kalavini Leatigaga tries; Sam Briggs 4 con) Whanganui 14 (Jamie Hughes, Alekesio Vakarorogo tries; Ethan Robinson 2 con). HT: 28-0