A word for someone succeeding at something due to a series of coincidences

"Lucky" can apply to any fortunate situation.

What I'm thinking is a situation where two people of equal skill face off in a competition of sorts. They have never faced each other before and have no knowledge of the other person's play-style. Yet one of them defeats the other with ease due to their play-style coincidentally countering the other's. When player A does Z, player B does Y simultaneously, over the course of dozens of engagements, which happens to favor player B.

"Lucky" feels too generic a word for this situation.

serendipity from Lexico:

The occurrence and development of events by chance in a happy or beneficial way.