Players have to determine which teams play, on which servers, and when. All this is decided before hand. They can use the space here to confirm the dates, times, servers and teams. Hence, it is run very much like a traditional knock-out competition.
The reason why it isn't a round-robin system is because later a round-robin will not be able to support the numbers of people involved in subsequent competitions.
Teams have been registered before hand, and times have been set, and servers, so that everyone know who they are playing, and who they may play. This has been done randomly, with the option of seeded teams from THE BOWL (or they might be seeded from a previous CUP competition).