Pokemon Diamond - Mesprit

[Stitch]

I'm in the middle of chasing Mesprit round trying to catch it and i've tried a few quick balls and ultra balls and i just can't catch it without it running. I don't want to use my master ball yet because apparently theres another pokemon later in the game that runs away just like Mesprit so i'm saving it.
I've tried to send it to sleep but i say i want to use hypnosis then it says Mesprit has fled.

Has anyone got any tips to catch Mesprit without using a master ball?

[Jam]

(Don't Quote Me On This But) To My Mind There Isn't Another Roaming Pokemon, TBH I Would Leave It Is Not Important But Otherwise It Really Does have To Be A Master, Sorry.

[Danny,]

use golbat to mean look it and then get its hp down with golbat, then let it flee and then get some more quick balls and throw them at it next time you see because it will still have the low hp.

[Oni]

Its rubbish dont use it, its seriously SERIOUSLY poor. I gave mine to my next door neighbour.

[Stitch]

use golbat to mean look it and then get its hp down with golbat, then let it flee and then get some more quick balls and throw them at it next time you see because it will still have the low hp.

Thanks +rep I've nearly got it i just need to train my golbat so it's speed rises then i can keep throwing balls at it.

Its rubbish dont use it, its seriously SERIOUSLY poor. I gave mine to my next door neighbour.

Well I want it.