8th point question

I'm at 7 points (with or without a unit at a BF),

my opponent has a temp sprite token on a BF,

I pass turn,

his/her sprite temp activates,

I ambush in with Rengar Trophy Hunter,

Opponent has no response,

Do I win on their turn? Or would I still have to hold to 8?

In addition, does it matter if I had a unit at the other BF beforehand?