This is the 16382nd most frequent Russian word.
решающими
"Decisive" or "crucial."
Here, 'решающими' describes factors, indicating they were key or decisive in determining the outcome.
Решающими факторами успеха стали упорство и труд.
The decisive factors for success were persistence and effort.
'Решающими' is predicting the decisive role of compromises in the future of the negotiations.
В этих переговорах решающими окажутся компромиссы.
In these negotiations, compromises will turn out to be decisive.
In this case, 'решающими' attributes a defining and crucial characteristic to certain moments in the game.