Chris Burnett was the only shining light for the home XI – his 65 runs off 74 balls standing out like a beacon.
Chasing 144 to win, Ohoka got off to a shaky start, reduced to 20/2, with Mariu making a golden duck, before former Cheviot player Will Hamilton took over the match, smashing an unbeaten 81 off 63 balls and leading his side to a comfortable seven-wicket win with 21.1 overs remaining.
A tricky wicket at Mandeville produced a tight encounter between struggling Southbrook and a powerful Darfield side.
The 'Brook were cruising at 94/3, with Canterbury legend Shanan Stewart (29 off 83) and keeper-batsman Gus Mowat (27 off 59) grinding out a decent first innings total.
But when they fell in quick succession, Southbrook shuffled to lose six wickets for 36 runs, stuttering to 130/9 in their allotted 45 overs.
Even with the low score, the 'Brook felt they were in the hunt, with batting proving difficult.
Darfield got off to a solid start with Zak Foulkes (13) and Nick Gilbert (18) before the Brook clawed back into the encounter.
Canterbury rep Henry Shipley got one that kept low off promising youngster George Gunn who snared two wickets and Darryn Boyle also nibbled out two more.
But the damage had already been done and Jesse Frew's unbeaten 33 saw Darfield to a hard-fought four-wicket win.
Sefton thumped Weedons after amassing 261/7 in their 45 overs, with contributions through the order and every batsman showing aggressive intent.
The big total was too much for Weedons who fell almost 100 runs short.
Lincoln had the bye while the last fixture of the round was abandoned due to a water-logged pitch at Pearson Park.
Oxford, at the base of the Canterbury foothills, saw more rain than most of the region last week, and although club volunteers covered the main oval block, the 50-60mm of rain that fell proved too much, sneaking under the covers at one end and making it unplayable.
Short scorecards:
• Cheviot 143 (C Burnett 65, S Burnett 21; H Williams 4/18, R Mariu 4/18)
Lost to Ohoka 144/3 (W Hamilton 81no, H Fitzpatrick 26no; C Burnett 3/14).
• Southbrook 130/9 (S Stewart 29, G Mowat 27; J Frew 3/17, Z Foulkes 3/21, L Foulkes 2/18)
Lost to Darfield 133/6 (J Frew 33no; D. Boyle 2/6, G Gunn 2/16).
• Sefton 261/7 (C Warner 48, L Taylor 45, M Smith 34, M Campbell 32no, T Harrison 23, N Granger 22; J Richards 2/34, C Robson 2/50)
Beat Weedons 170.
• Oxford-Rangiora vs Leeston-Southbridge match abandoned.