Harry was selected because the fake 'Mad-Eye', who turned out to be a follower of Voldemort by the name of Barty Crouch Jr, had put Harry's name in the cup in hopes that he would make it to the end and be transported to the Death Eaters who were resurrecting Voldemort.
Barty Crouch Jr, a death eater posing as Alastor 'Mad-Eye' Moody, entered Harry's name into the Goblet of Fire under a different school and confounded the Goblet into believing four schools were competing. Having only one name to choose from for the fourth school, the Goblet picked Harry.
The Triwizard Tournament
harry potter and the goblet of fire. it's a triwizard tournament
The Tri-Wizard Tournament.
The Quidditch Tournament The Triwizard Tournament The Yule Ball Holiday feasts
If you're asking about the competition in Harry Potter and the Goblet of Fire, it was the Triwizard Tournament.
He wins the Triwizard Tournament.
The four champions of the Triwizard Tournament were Harry Potter, Cedric Diggory, Fleur Delacour, and Victor Krum.
Harry Potter and the Goblet of Fire. It was during the first task of the Triwizard Tournament.
Three, Hogwarts Beauxbatons and Durmstrang
A hint.
Poliakoff is the surname of a Durmstrang student who came to Hogwarts during the Triwizard Tournament.
That would be Harry Potter and the Goblet of Fire. In which the Three Schools participate in the Triwizard Tournament.