Q&A for How to Catch Mesprit in Pokémon Diamond and Pearl

You will still encounter Mesprit if your lead Pokémon is Level 50 or lower. However, if your lead Pokémon is above Level 50, a Repel will prevent Mesprit from appearing.

Yes, as it is a ghost/dragon type Pokemon so it should work. Some quick balls maybe needed, though.

Catch Palkia or Dialga, then go where you got attacked by Starly. Surf to the cave then chase Mesprit.

Yes, but once the Pokémon with mean look faints, the Mesprit will flee again.

You can use a Quick Ball. Since Mesprit flees after the first turn, deploying a Quick Ball immediately upon encounter can be effective, though it may require multiple attempts.

You can use either a Master Ball or a Quick Ball. The Quick Ball is generally a better choice, allowing you to save your Master Ball for more challenging captures like Giratina.

To increase your Pokémon's speed, use Carbos. You can find it in your medicine bag or purchase more in Veilstone City. Carbos permanently raises the speed of the Pokémon it is applied to.

Yes, the Quick Ball offers the highest catch rate during the first two turns of battle, surpassing even an Ultra Ball in effectiveness. This makes it your best option after a Master Ball.

Mesprit has a base speed of 80. Its exact speed stat will vary based on its level, Individual Values (IVs), Effort Values (EVs), and nature. To ensure you can outspeed it, you will need a Pokémon with a higher speed stat.

You should continue to use Quick Balls. Aside from Master Balls, they are often your best option, particularly when used at the very beginning of a battle due to their increased catch rate during the first turn.