Student or Learner
If one of the two teams weren't playing good, would it make sense to say "If they keep on playing like this, the rout is going to be on in the second half."?
It's not usage I'm familiar with. I'd say "It's going to be a rout" but not "the route is on."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
"The rout is on" is common in the football world I know. Like, "The Hawks were leading by 2 touchdowns at halftime. They scored to begin the second half, then returned an interception for a TD on the next play and the rout was on."