This is unlocked through story progression. Very minor spoilers ahead.
This is unlocked in Suvia, where Lady Lumia asks you to investigate a missing machine part.
You will go through the sewers and then warehouse to find machine parts at the end (this turns into PAT later).
Report back to Lady Lumia to be told that tournaments are now open.
Warp to Zaber and complete the first tournament.
Afterwards, come back to Suvia and take part in the second tournament, however:
After this, return to Lady Lumia and as soon as you speak to her, this achievement should unlock during the cutscene.