The correct preposition in both sentence is "in."
The preposition "at" could also be used in the first sentence.
Which structure is correct?
We won at/in that tournament.
Are you participating at/in that tournament?
4 answers
Either "at" or "in" could be used in the first one?
Yes, it could! But "in" is probably the better choice. A tournament takes place at a specific location, so "at" might be appropriate.
Yes.
2 answers