How do i get my puppy to go to the toilet in a certain place in the garden?

I have a 13 week old border collie, he is really good, house trained except the odd little widdle now and then. We have a slabbed back garden so the mess isn't too much of a problem but is there any way we can get him to go in one corner of the garden only?
He learnt to lay down today yipee!!

each and every time yiou take him out for toilet, take him to the spot on the lead.

keep it light and relaxed and reward him

any reason why just the one spot, it may make your toilet trainer harder