Singh and Dhinga shared an opening stand of 50 before Dhinga departed.
Phelps said Jeremy Tucker was unlucky to be run out, on three, with the score at 67 after a straight drive from Singh was deflected on to the stumps by the bowler.
Phelps and Singh then added 57 runs before Phelps was dismissed, leaving Singh and Ajay Kumar (14 not out) to see HSOB home. Singh brought up his hundred with a four.
The 27-year-old Singh usually plays his cricket for Greerton in Tauranga but returned to Gisborne along with another former HSOB player, Gary Singh.
HSOB medium-pace bowler Baljeet Singh, Gary Singh and Ryan Majstrovic played their parts in the win as Boys’ High were restricted to 155-9 with Baljeet Singh taking three wickets for 30 runs off six overs.
Davenport top-scored for Boys’ High with 53 off 51 balls. His innings included three sixes and three fours. Rowe was the next best batsman, with 28.
Horouta went into their clash with defending champions Kevin Hollis Glass Pirates with a three-from-three win record.
On Saturday, they had dismissed HSOB for 36, thanks to a career-best 6-12 from Blake Taylor, while Marty Brandso continued his good form with figures of 4-23.
Pirates were chasing their second win of the weekend after Richie Needham had ripped through the Campion batting to finish with 6-8 as the students were all back in the pavilion with only 37 runs on the board.
With Horouta skipper Bryan Forde unavailable, Greg Taylor and Francis Gray opened the batting, and a disastrous run-out put them on the back foot.
A combination of tight bowling and poor shot selection meant a steady flow of wickets as Pirates captain Mitchell Turner and Needham each picked up three wickets.
“We had a small recovery, which saw us through to 99, but that was never going to be enough to beat Pirates,” Greg Taylor said.
“We needed at least another 30 runs.”
Although Pirates lost three quick wickets, they had four wickets in hand when they reached their target.
Campion stayed in the hunt for a playoff place when they beat GBHS (2), who have yet to win but are improving with each outing.
Boys’ High batted first and posted 105, with player-coach Paul Jefferson and Angus Orsler sharing a 53-run second-wicket partnership.
Openers Jamies Torrie (co-captain) and Hunter Jones took the game away from their high school rivals, with Torrie scoring an unbeaten 64 and Jones not out 37 as Campion replied with 106-0.
Sunday scores: Pirates 102-6 (Mitchell Turner 22 not out, Brad Reynolds 22; Keegan Martin 3-27) def Horouta 99 all out (Keegan Martin 23; Mitchell Turner 3-23, Richie Needham 3-24).
HSOB 156-3 (Sam Singh 101no, Ajay Kumar 14no) def GBHS (1) 155-9 (Jarrod Davenport 53, Jak Rowe 28; Baljeet Singh 3-30, Gary Singh 2-27, Ryan Majstrovic 2-37).
Campion 106-0 (James Torrie 64no, Hunter Jones 37no) def GBHS (2) 105 (Paul Jefferson 33, Angus Orsler 24; Patrick Mathers 2-10, Marshall Norris 2-20, Hunter Jones 2-20).
Saturday: Horouta 37-4 defeated HSOB 36 (Blake Taylor 6-12, Marty Brandso 4-23).
OBR 195-8 (Nick Greeks 52, Craig Christophers 41, Carl Carmody 30, Evan Mooney 23) def GBHS (2) 85 (Jonathan Purcell 2-2, Matt Cook 2-15, Zane Boyle 2-27).
Pirates 38-4 (Benito Barry 2-27, Zeppo Paige 2-44) def Campion 37 (Richie Needham 6-8, Mitchell Turner 3-16).
