Let's say for the sake of argument that Russia wins the Russo-Japanese War decisively, at sea and then forcing Japan to a stalemate and surrender on land.
Coming off of this victory the Russians suppress the 1905 Revolutions.
The Anglo-Russian Entente of 1907 was signed shortly after, and Russia began to concentrate its efforts in Pan-Slavism.
So if Russia was cockier due to victory would they challenge Britain in Persia and Central Asia instead of messing around in the Balkans? Would they start something with the Ottoman's again?