Test case [C2] has a precondition [C1]
Dependency Flow Chart:
When clicking on this it shows you a tree of tests and there dependencies so, C1 would lead onto C2.
The benefit of this is that you can see which tests have the most dependencies which could also help you gauge the priority/importance of a test case.
Following on from this, when creating a test plan, you could Automatically order tests by there dependencies which would means tests such as Logging into the Client would appear at the start. Tests with no dependencies could be ran at the end, or at the start if you desire.