Is there any other way to catch mesprit besides using masterball.?

You can use any pokeball on mesprit. I would suggest first having a Pokemon with mean look and holding the item quick claw. That will make them attack first, and make your Pokemon use mean look so mesprit won't escape. Then I would suggest buying timer balls, quick balls, loads of ultra balls and great balls and maybe some net balls if you have a Pokemon higher lvl than mesprit. Use the quick ball first since it works best at the beginning of a battle.

You can use any pokeball on mesprit. I would suggest first having a Pokemon with mean look and holding the item quick claw. That will make them attack first, and make your Pokemon use mean look so mesprit won't escape. Then I would suggest buying timer balls, quick balls, loads of ultra balls and great balls and maybe some net balls if you have a Pokemon higher lvl than mesprit. Use the quick ball first since it works best at the beginning of a battle.

Buy at least 100 Ultra balls and try to catch it with a wobuffet.

Get it down to just ONE HP(use False Swipe), put it to sleep or paralyze it, then just chase it around Sinnoh while chucking Ultra Balls at it. You can use Dusk Balls at night for a better chance.

Set your DS clock to sometime at night. Go to Snowpoint and buy Dusk Balls(about 30 should do. There may be other places that sell Dusk balls but I can't think of them). Go out looking for Mesprit and use Dusk balls. That is how I got mine

Any damage you do to him stays even if he flees the damage will still be there

You could weaken it then make it go to sleep or paralyze it and use duskballs highly recommended

Just get a fast Pokemon that knows Mean Look or possibly Hypnosis, weaken it, and then throw different balls at it.I advise to bring a lot with you because it can be tricky sometimes since it doesn't stay in the ball a lot.also save before you encounter it; you don't want to accidently beat it or you may have to retrack a lot.

Ok. Get a Pokemon that knows firespin, whirpool,ect.(These moves make a Pokemon not able to flee.)Now lower it's HP down to red and try using some ultraballs. You could also use dusk balls if it is in the nightime. It is 4x better for dusk balls to be used in the night and not the day.

P.S Save in the area were Mesprit is. You may kill it so this is a helpful step. Also I wouldn't put Mesprit in your lineup. It isn't a great pokemon!

Yeah. Having his health down in the red zone and sleeping/paralyzed. Then, using dusk balls at night. This should be much easier.