Rovers' chances of reaching the finals series were all-but ended on Saturday when rain forced their fixture with United to be abandoned while Rovers were halfway through their run chase.
United were victorious based on their current position and the result drops Rovers to sixth position on the ladder and leaves them nine points outside the top four.
Rovers bowler Matt Scott said he believed they would have earned the victory if they were able to bat out their innings.
"It was disappointing. We were confident of getting the job done," Scott said.
"Mitch and Lachlan were batting well and we thought they could steer us home.
"But unfortunately the rain came. It's unfortunate for us but handy for the farmers."
Rovers still have a mathematical chance of advancing but they will need other results to go their way.
"We need pirates to lose both of their remaining matches and we need to win both of our last two games to have a chance," Scott said.
Rovers were their own worst enemy in their match with United and it proved costly.
"We dropped a couple of chances in the field and we didn’t bowl as well as we could have but we still thought 250 was a par score so it was good to keep them to 225," Scott said.
"Our run chase started well with Cal McKiernan scoring some runs quick and we were in a good position but then we lost two quick wickets before Jack Bennett was able to steady the ship.
"At drinks, we knew we were behind the run rate and Lachlan and Mitch went back out and scored some quick runs but the storm came a bit sooner than we liked."
Scott admits the side will need to produce a miracle to reach the knockout stages.
"We know we are going to be at our absolute best when we come up against Wingham this weekend. They are the bench mark but Nulla showed they can be beat," Scott said.
Wingham currently sit on the top of the competition table and will have the benefit of playing on home soil on Saturday.
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