Mr Norrie was apparently unwell toward the end of the first set, which I missed: the discussion on Sky between sets (when he took off to the "locker room" for an extended period - I don't know if it was an MTO or just a Delhi-belly break) was about how he had never retired part way through a match. He wasn't playing very well when he came back to court - lots of fruitless serving and volleying in an attempt to shorten points. The opponent kept his concentration well, and just cruised.
Thanks for the report, christ. While it's not great news that Cam was unwell (let's hope with a short-term bug rather than an injury), it's at least a better reason for the loss than "he just played badly."