Workflow Rule using a custom lookup field

I'm trying to write a workflow rule that updates a picklist field to a certain value when an lookup item is selected.

Action - When lookup account name = ABC, then update picklist field name to ABC

Here is what I started with, but way off I'm sure. Any help or insight would be appreciated.

Lookup field: Primary_Competitor__r.Name

Picklist field: Competitor__c

=============================

IF(

 Primary_Competitor__r.Name = "ABC)"

)

ISPICKVAL( Competitor__c, "ABC")

)

Syntax error :)