Why is the cause "serbia was helped by the triple entente alliance" relevant to WW1?

Austria tried to bully Serbia after the archduke of Austria was inated and upset the balance of power in the Balkans. Russia moved to oppose Austria's ambition in the region. Russia was one of the three entente powers, the other two were France and Britain. France and Britain would not have become involved in the war had it not been for their entente alliance with Russia.