A victory at the weekend would have kept the Bay's chances alive but Cashmore admitted now the more realistic target was a mid-table spot and the push for that would start against North Harbour on Friday.
"Losing at the weekend pretty much puts us out of the semis but we don't want to finish at the bottom end of the table. We want to finish mid-table or as close to the top as possible. We want to win on Friday," he said.
"We're not far from it. It's just the little things we're not doing in the last 10 minutes which are proving costly. But we're growing in confidence each week and we know that we can put Harbour away.
"I know that if we had beaten Wellington we had a definite chance of maybe making it. We just need to put some points on the board and get some wins really."
There were only fingertips in it for Thomas Waldrom's match-winner for Wellington with the video referee Kelvin Deaker ruling the forward had got downward pressure on the ball.
For the Steamers it was a cruel blow after battling back from a 23-8 deficit at half-time to take a 32-23 lead with 15 minutes to go.
"It sure was (a heart-breaker)," Cashmore said. "It's been two weeks in a row because we put Auckland away the week before (before losing 41-30) and the same thing against Wellington.
"There are probably a few reasons (why it's happening). We're losing a little bit of focus towards the end of the game and we're not really nailing it home.
"We had them on the ropes and we got ahead and we had them and there was a lapse in concentration and we just didn't finish them off."