I don't think Novak was very well. He is on a gluten-free diet so it could be something to do with his stomach. At the French Open he was thanking his team in his speech for 'putting him together' for the tournament. I wondered then what he was on about and that was only a few weeks ago. He looked a bit gaunt during his match.
Somehow I don't think Murray will have an easy match against Krygios tomorrow.
Novak didn't look himself. I do hope that he is OK. Hopefully having a nice rest and some time with his family. Fair play to him though for not saying what was wrong, which could have stolen some of Querry's thunder and it being a private matter for him and up to him what if anything to divulge.