To my ear it depends upon context:
Qualified in implies that there is a formal process of qualification. For instance, "I qualified in marksmanship."
Qualified for implies that you have satisfied enough requirements to meet criteria. "I qualified for acceptance into the program." "I qualified for a loan."
You can also say "I am qualified for the job." But you wouldn't say "I am qualified in the job." - unless there is a formal process for doing so.
This may have some dialectical variation, and I am speaking strictly from the POV of a native American English speaker. (e.g. I believe the British speak of qualifying in school levels which we do not use in AE.)
As to your usage above: it sounds strange to my ear without context to back it up. As I have said, it largely depends upon how it was meant. If you meant, "I was advanced due to winning" then yes it is correct. If you meant, "I was able to compete because I had the necessary experience," then I would use "qualified for."