Here is what Roger Federer said in his press conference :
“I feel for the crowd. They’re there to watch good tennis, proper tennis. At least they see the two of us who gave it all they had. They saw other players that tried at least. His explanation to me is that he felt too much pain on the serve, maybe on the jump. That’s what he told me. It’s getting worse. At that point obviously when you’re down a set and a break, it’s getting worse, he’s in pain. I see the point. If you feel like it’s getting worse and you can hurt yourself even further, it is better to stop."
“I feel for the crowd. They’re there to watch good tennis, proper tennis. At least they see the two of us who gave it all they had. They saw other players that tried at least. His explanation to me is that he felt too much pain on the serve, maybe on the jump. That’s what he told me. It’s getting worse. At that point obviously when you’re down a set and a break, it’s getting worse, he’s in pain. I see the point. If you feel like it’s getting worse and you can hurt yourself even further, it is better to stop."