Yes, in these sentences, "to + infinitive" is being used to express the reason for the feeling (thrilled).
- "I was thrilled to win the game for the first time." → I won the game, and I feel thrilled about it.
- "I was thrilled to be chosen." → I was chosen, and I feel thrilled about it.
- "I was so thrilled to get the report." → I got the report, and I feel thrilled about it.
So yes, in these cases, the "to + infinitive" refers to something that has already happened. However, in different contexts, it can also refer to a future event (e.g., "I'm thrilled to meet you", meaning I haven't met you yet but am excited about it).
A simple tip:
When "to + infinitive" follows an adjective (like thrilled, happy, sad, surprised), it usually explains why you feel that way.
To check if it refers to something past or future, look at the context:
- If the event has already happened, it refers to the past (e.g., I was thrilled to win → I already won).
- If the event is going to happen, it refers to the future (e.g., I'm thrilled to meet you → I haven’t met you yet).