Greerton led 10-3 at the break and guided by astute tactical kicking from first-five Elliott Davies took control. Tries to hooker Tane Howe and flanker Joe Key had them ahead 22-6 before a brilliant solo try to promising flanker Sioeli Alofi fired up Whakarewarewa.
When captain Doug Edwards crashed over soon after it was all on but Greerton held on gamely for a well-deserved win.
A decision by Auckland referee Angus Mabey to disallow a bonus point try to Greerton in the final play of the match may be crucial in the final wash-up next week.
No 8 Joe Tupe was a towering force for Greerton and his form and fitness is good news for all Steamers fans.
"I was very pleased with the boys' efforts and how they stayed composed especially on defence. We held our ground and hopefully were able to force an error," Tupe said.
"It was hard times for me last year with injuries keeping me out for several months but each time I play I am getting more confidence."
Mount Maunganui Sports beat Whakatane Marist 40-15 to retain top spot with one round to play.
BOPRU Baywide Results May 28
Premier:
Greerton Marist 22 (Taylor Jones, Tane Howe, Joe Key tries; Elliott Davies 2 con pen) Whakarewarewa 20 (Sioeli Alofi, Doug Edwards, tries: Ryubyn Vaipo 2 pen, 2 con) HT 10-6
Rangataua 28 (Lalaki Foketi, Sasu Wihapi, Mark Roberts tries; Sasu Wihapi 3 pen 2 con) Rotoiti 20 (Joe Royal, Josh White, Shilo Cullen tries; Logan Henry pen con) HT 13-10
Te Puke Sports 46 (Danny Underwood 2, Conor Hirini, Kosuke Enomoto, Brad Armstrong, Caleb Hall, Alex Thrupp, Andy Lee tries; Dan Hollinshead 3 con) Opotiki 0 - HT 26-0
Mount Maunganui 40 (Logan Gies 2, Ngatai Kingi, Sam Mayes, Isaac Te Aute, Matt Axtens tries; Pera Gibbs 5 con) Whakatane Marist 15 HT 19-10
Tauranga Sports 24 (Brad Nickel, Nick Evemy, Dan Stroud, Paul Morris tries; Nick Evemy 2 con) Paroa 15
Te Puna 34 (Jeff Thwaites, Wally Mill, Ben Kirby, Mitch Holton, Hamish Boyce tries; Keegan Long 3 con pen) Arataki 20 HT 20-10
Division One:
Marist St Michael's 27 Ruatoki 21, Ngongotaha 55 Katikati 15, Poroporo 54 Papamoa 10, Rangiuru 30 Waikite 20, Kahukura v Te Teko postponed.
Development:
Mount Maunganui 45 Whakatane Marist 32, Tauranga Sports 57 Paroa 3, Te Puke Sports 15 Opotiki 7, Greerton Marist 85 Whakarewarewa 12, Te Puna 27 Arataki 15, Rangataua 38 Rotoiti 12.
Baywide Premier Points:
Mount Maunganui Sports 42
Tauranga Sports 39
Whakatane Marist 35
Te Puna 33
Te Puke Sports 32
Rangataua 32
Greerton Marist 26
Rotoiti 23
Whakarewarewa 22
Opotiki 7
Arataki 7
Paroa 4
Baywide Development Points:
Te Puke Sports 47
Mount Maunganui Sports 44
Tauranga Sports 41
Arataki 36
Whakatane Marist 34
Te Puna 30
Rangataua 23
Greerton Marist 20
Whakarewarewa 11
Rotoiti 10
Opotiki 9
Paroa 5
Baywide Division One Points:
Ngongotaha 34
Poroporo 33
Rangiuru 31
Judea 29
Waikite 27
Marist St Michael's 25
Te Teko 24
Kahukura 11
Katikati 10
Ruatoki 9
Papamoa 5
