Catching MESPRIT and AZELF

Ok, I've read all these different ways of catching these two pokemon, but can anyone tell me the best way to catch them?

THanks to those who reply. ^^

The best and only easy way to catch them is a Master Ball. Unfortunatley, those are obviously in short supply. What I did to catch them was wait til night, weaken them, put them to sleep, and keep throwing Dusk Balls until I got lucky and caught them. It may take a while, or maybe just a lot of luck, but it does work. If you run out of Dusk Balls in any given attempt, just reset the game and try again.

Also, I want to point out that this works for pretty much every legendary pokemon. I caught them all with Dusk Balls.

i caught all my legendarys in timer balls, i just took a high lvl pokemon with high defence and weakend the legedary util red and then just took hits and threw all the balls i had:D. Used a potion once in a while, and everytime the pokemon was caught it was timer ball