Setting up rivalries was a Stalin tactic. After he died men around him said it was the only reason he remained in power. He set up rivalries so everybody would be suspicious of everybody else and no one trusted anyone enough to effectively plot against him.
The race to Berlin between Marshals Zhukov and Konev is a good example.
When Hitler invaded Poland, ranking officers found Stalin literally hiding under his desk because he was sure he was going to be assassinated.