Verified answer

Catch a wabbafet (however you spell it) so it can't flee then damage it but with out killing it then try your luck with great balls . & by finding it get to a place were you can go from route to route use a max repel but your first pokemon in your party has to be lower level then azelf, this will prevent any other pokemons lower lever then you to attack you .

If you don't want to use a masterball:

- train up a pokemon that can learn false swipe and teach it to them. They can reduce another pokemon down to 1hp but won't make it faint using this move. Train it untill it's speed is high enough to make a move before the azlef runs and use this every time you get a chance.

- train up a second pokemon that can use a sleep inducing move. Again, train that pokemon so it's speed is higher than azlef. Put azlef to sleep and then keep throwing ultraballs at it while it has 1hp and is asleep.

all i can say is that your a noob just look at your team. your the noobest of noobest.

but here is the trick, damage azelf until it hits its red life and use something like sleep or paralyze on it and throw about 5 dusk balls and you should catch it