He's always talking about Del Potro as this incredible specimen who will be winning lots of Slams and will be giving nightmares to all the top guys. He's said this several times before and said it again this week. I've never seen him say this about any other player on the tour at any point. It's like Del Potro is his younger brother or something with the way he talks about him and hyping him?
Federer seems to really like him a lot.