It's remarkable she [Venus Williams] plays at all, given her Sjögren's syndrome [an autoimmune disorder that can cause joint pain]. She's back, winning tournaments. She didn't allow society to tell her, 'You have this disease; you can't do that anymore.' I look at her, like, 'She's not playing at 100 percent. You are. You don't have excuses.' Knowing what she went through helped me try to be a more positive person.