This is the 233rd most frequent Turkish word.
sonucu
"Sonucu" means "the result" or "the outcome" in English.
The word 'sonucu' in this sentence acts as the object of the sentence with a possessive suffix indicating 'of the match'.
Maçın sonucu belli oldu.
The result of the match has become clear.
Here, 'sonucu' indicates the effect or outcome of the noun preceding it ('long work').
Uzun çalışma sonucu başarıya ulaştılar.
As a result of long work, they achieved success.
In this case, 'sonucu' indicates consequence due to the actions described.