When Austria- Hungary took lands in the Balkans and they kept Russia out with the help of Germany Russia hated their alliance.
Russia and Austria-Hungary And Turkey, depends which period you are asking about
Austria, allied with Russia in the late 18th century had come to fear Russian influence in the Balkans. Specially after its defeat by Prussia in 1866.
Germany, China, Austria
The powder keg of Europe refers to the Balkans, and various European powers that laid claim to the territory. Those countries primarily included Russia, Germany, and Austria-Hungary.
The Balkans.
The Archduke of Austria Franz Ferdinand was assassinated by a Bosnian-Serb. In retaliation Austria-Hungary gave Serbia an Ultimatum of demands designed to destroy Serbia's influence in Bosnia. Serbia rejected the Ultimatum and Austria-Hungary declared war on Serbia. Germany was Austria-Hungary's ally and agreed to assist Austria-Hungary in the invasion of Serbia. Russia, fearing an invasion of Serbia would end it's own influence in the Balkans began to mobilize for war. As a result, Germany declared war on Russia.
The Balkans."The more immediate cause for the war [World War I] was tensions over territory in the Balkans. Austria-Hungary competed with Serbia and Russia for territory and influence in the region and they pulled the rest of the Great Powers into the conflict through their various alliances and treaties." -Wikipedia
they became rivals in the balkans because they both wanted the power to control it and the Dardanelles.
Russia and Austria-Hungary
In 1914, the desire to control the Balkans was primarily held by Austria-Hungary and Russia. Austria-Hungary aimed to expand its influence in the region to counteract Slavic nationalism, while Russia sought to support Slavic populations and assert its dominance in the Balkans as a protector of Slavic nations. This tension contributed to the outbreak of World War I following the assassination of Archduke Franz Ferdinand of Austria in Sarajevo. The Balkans were seen as a strategically important area, leading to increased rivalries among the great powers.
Russia's motive in supporting Serbia during the crisis of 1914 was to protect its Slavic ally and maintain its influence in the Balkans against Austria-Hungary.