Glad you found something that works for you! Killing weeds is good for your soul.

It'll probably keep coming back. It's a spreading grass (which is why it's called creeping bentgrass) so it'll spread if the area next to it is bare.

Oh no, Paul James the Gardener Guy's manual method, maybe I will buy a goat. Better yet, I will pay the neighborhood kids $10 a bushel for all the grass they can pull from the clumps. Will need to try watering before pulling. Anything has to be better. (Propane torch?, Nah.)

my guess was creeping bentgrass too, and thanks Iawniac I didn't know tenacity controls it because pretty sure Drive XLR8 doesn't. if it were zoysia then the was zoysia there before and its tough roots system stayed alive even though you overseeded cool season grasses. If you're lucky the zoysia will eventually choke everything out and give you full zoysia (it's super dense and drought resistant but it'll go dormant brown very quick in Canada, goes dormant so quick that it should have been all brown weeks ago there and you'd not have pics of green blades), looks too stringy and thin to be zoysia anyway my guess is still creeping bentgrass or similar. Do a google image search of creeping bentgrass and scroll to see similar pics of the plants pulled out like yours. CBG is a perrennial so maybe you can live with it, it should fill in dense too, so dense I just read some putting greens use it but those are mowed very often to create a tight nit and also would need lots of water to cut anything that low without killing it.