Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Who became the champion for the 1984 Grand Prix where Marty Davis was the runner-up?

### Inputs:
table_name: table, columns: ['Week of', 'Tournament', 'Champion', 'Runner-up', 'Semifinalists', 'Quarterfinalists']

### Response:
SELECT Champion FROM table WHERE Runner-up = Marty Davis