In a thrilling contest on Saturday, the ladder leaders overcame the winless Mathoura by just one shot in a rollercoaster ride.
The match was ultimately decided by Rich River's winning rink which included Gary Radford, Peter Nesbitt, Bruce O'Neale and Eugene Xodo.
The quartet was able to hold one for a one-shot win in its respective match-up.
It came after the two sides spilt the other two rinks, with both games decided by 18 shots.
“You can't get any closer than that,” Radford said.
“Our own game was extremely exciting. We came from behind to grab the lead and then almost lost it on the last end after we gave up two shots.
“Joe Murphy from Mathoura deserves a lot of credit for his performance. There was nothing our guys could do against him.”
In other division one matches, Echuca made it two wins on the bounce thanks to a six-shot victory over Mathoura.
Meanwhile, Moama got the better of Rochester by eight shots.
Saturday's results now set up a huge clash between Moama and Rich River this weekend.
“We're really looking forward to it,” Radford said.
“We want to test ourselves against Moama and they'll provide a good indication of where we are at as a team.”
Heading into the weekend, there could be some adjustments to the fixture with temperatures of 40 degrees (Friday) and 44 (Saturday) forecast at the time of writing.
Under CVBD rules, games would start at 9am on both days if the forecast remains above 38 at 11am on Thursday.
But CVBD president Barry Brown said any decision made about games going ahead would use "common sense and would put the safety of players first.”
Division 2 results: Echuca 55 def. Tongala 45; Moama 89 def. Rochester 37; Rich River 60 def. Mathoura 58.
Division 3 results: Elmore 63 def. Lockington 51; Mathoura 68 def. Rich River 56; Moama 86 def. Rochester Red 49; Echuca 83 def. Rochester Green 45.
Division 4 results: Tongala 84 def. Elmore 47; Echuca 72 def. Lockington 42; Moama 78 def. Ky Valley View 36; Rich River 63 def. Mathoura 53.
Mid-week results: Echuca White 81 def. Ky Valley View 32; Moama Red 88 def. Elmore 30; Rich River 87 def. Echuca Blue 42; Mathoura Red 96 def. Mathoura Blue 38; Tongala 61 def. Moama Green 54.
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