Both teams got four tries, so once again the boot of James Lash proved the difference, along with scoring two tries in a 19 point haul.
Lash continues to play leap frog with Wanganui's Craig Clare at the top of the points scorers list, now leading by two on 80 points.
Thames Valley continue to make good on their potential after they travelled down to Te Kuiti and upended King Country 45-36 in an open game.
Similar to Wanganui's loss to Mid Canterbury, the home team were left to rue some discipline issues, as Jarrod Goodall and Beau Hamilton combined to kick four penalties for Thames Valley, which proved the difference with both teams scoring five tries and converting four.
It gives both Wanganui and King Country something to think about heading into their clash at Cooks Gardens this weekend.
Horowhenua Kapiti consolidated their Top 4 spot, with their round robin game against Wanganui already looming as season-defining for both teams, after they dismissed East Coast 52-3 in Levin.
David McErlane scored three of his team's seven tries, with James So'oialo contributing 16 points.
West Coast's progress was dealt a big body blow after they were beaten 36-19 in Gisborne, falling from fourth to seventh, as Poverty Bay came from behind at halftime to keep alive their hopes of the Lochore Cup playoffs with their second win.
Andrew Tauatevalu scored 21 of his team's points.
South Canterbury will still be expecting a tough game from West Coast in Greymouth this week, but with Wairarapa Bush at home and East Coast away to finish the round robin, they will be confident of getting the top spot.
Wanganui, on the outside looking in for a home Meads Cup semifinal, must make their way through King Country at home, Horowhenua-Kapiti in Levin and North Otago at home while hoping other results go their way if they hope to be in the Top 4 come October 14.
Results
Buller 29 (James Lash 2, Erenimo Tau, Josh Tuidriva tries; Lash pen, 3 con) bt Wairarapa Bush 24 (Epeli Rayaqayaya, Robbie Anderson, James Pakoti, Soli Malatai tries; Tim Priest 2 con).
Horowhenua Kapiti 52 (David McErlane 3, Willie Paia'aua, James So'oialo, Ryan Shelford, Robert Millar tries; So'oialo pen, 4 con; L McMahon 3 con) bt East Coast 3 (Kris Palmer pen). HT: 10-3
Thames Valley 45 (George Lelenoa, Jarrod Goodall, Hayden Wisnewski, Harry Lafituanai, Tyrone Keith tries; Goodall 2 pen, 4 con; Beau Hamilton 2 pen) bt King Country 36 (Kieron Rollinson, Rob Sherson, Alby Mathewson, Stephen Turner, Jesse Williams tries; Rollinson pen, 3 con; Stormy McCarthy con).
Mid Canterbury 40 (Maleli Sau 2, Willie McGoon, Christian Vainerere tries; Jarred Percival 4 pen, 4 con) bt Wanganui 39 (Cameron Crowley 2, Jona Sawailau, Timoci Seruwalu, Kaveni Dabenaise, Craig Clare tries; Clare pen, 3 con). HT: 31-24.
Poverty Bay 36 (Andrew Tauatevalu 2, Siosiua Koala, James Grogan, Anthony Karauria tries; Tauatevalu pen, 4 con) bt West Coast 19 (Amenatave Tukana, Todd Struthers, Steve Soper tries; Nik Cumming 2 con). HT: 19-14 West Coast.
South Canterbury 36 (Kalavini Leatigaga 3, Brad Hemopo, Vatiliai Tora, Willie Wright tries; Wright 3 con) bt North Otago 29 ( Lemi Masoe 2, Lisala Halaeva, Dan Lewis tries; Lewis pen, 3 con). HT: 22-15.
