On Tuesday he tweeted a picture of part of a menu showing a club sandwich and Japanese baked eel, along with the words: “Who would have thought the eel would be the safer bet!? Hopefully I’ll feel better tomorrow.”

The world number three said on www.europeantour.com on Wednesday: “It wasn’t good at all.

“I just had a piece of toast and a couple of bits of melon for breakfast and I came out here thinking that I would just to try to hit a few more balls, but even after making a couple of swings my stomach was too sore even to attempt another shot.”

McIlroy has been prescribed medication by the on-site doctor, and is confident he will be okay to head out alongside Rickie Fowler and Dustin Johnson in the first two rounds at Sheshan International Golf Club.

“He gave me antibiotics, Buscopan for the abdominal pain, and then some painkillers, too,” the Northern Irishman said. “So, I’ll be loaded up. It hasn’t been great. I was thinking of going out to play nine holes but I decided that it would do me more harm than good.

“I’ve played well here every time I have travelled – I haven’t finished outside the top 15. I’m hoping, providing that I feel a lot better, that I can really make a run at it.”