Harry Potter: Quidditch Champions

The Triwizard Titan achievement requires no online matches to be played.

The Triwizard Schools Quidditch Cup can be accessed through the menu by going to Play > Press A > Campaign > The Triwizard Schools Quidditch Cup. I believe you must have completed The Weasley Burrow Garden Cup (tutorials) and The Hogwarts House Quidditch Cup to access this Cup, although I could use confirmation on this.

This Cup contains four placement matches, and one tournament match. You will select which school you want to play as, and then play two placement matches against each of the other two schools. You do not have to win these matches. The placement matches keep a tally of total points scored, and after your four matches will use the total points scored for all three teams to determine seeding in the tournament. Only the top two schools qualify for the final tournament match, so make sure you end up in at least second place after the placement matches.

After the four placement matches, you will then play one final tournament match, which you must win in order to win the Cup. If you’re struggling to win matches, try restarting the tournament and selecting a lower difficulty.

Once you win the final tournament match, you win the Triwizard Schools Quidditch Cup and the achievement will unlock!

I hope this helps!