Big bertha spam with any of the following if need: razor, racketeer, TB, and silo.
While BB costs more than funnel, it's useful when you've only got one. Assuming continued investment from both sides the BB will gradually disallow funnels from leaving base, at which point you've got map control and even a viable threat to their base, while they have a ball only usable in defense if that.
Okay so not decisive in the sense you definitely kill funnels, but in a strategic sense it's a pretty damn hard counter.