Thanks for making that point to Front, though he'll never believe it. If the pain can be numbed or dulled, it will help, but it won't help the fact that he won't have the strength from the core. He seemed to figure out another way to make his serve work today. He's never had a powerful serve, only a good spot serve, so that is still Ok. The spin on his shots comes from core, though, and that will mess with his timing, as was evident today.
But another thing that is less noticed in Rafa's game is his tennis IQ and his familiarity with his opponents game. He knew where Fritz was going, which helped him not to have to move as much. Kyrgios is very unpredictable, possibly even to himself, so we'll see how well Rafa anticipates him, as I think that will be key, too.