Fox finished playing in Mexico at a World Golf Championship event on Monday [NZ time] and spent more than 15 hours in the air to get back to Auckland at 5.45am yesterday.
He then caught a flight down to Queenstown, arriving mid morning to get out and play some practice holes yesterday afternoon.
Fox was obviously feeling jaded and tired and said ''I don't really know'' when asked how he felt.
''I feel better than I expected to. I have not hit a wall yet but I am kind of expecting to. I got a lot of sleep on the way home,'' he said.
''Hopefully an early tee time tomorrow and still being on Mexican time, and a sleep-in on Friday will make me right for the weekend.''
Fox (32) said in Mexico he felt a bit light-hearted and dizzy - ''kind of felt drunk''.
He finished tied for 67th in Mexico after getting a last minute call-up and playing on what he admitted was a tough golf course.
''I felt like I played better than I scored. It was a tough golf course regardless of not having any preparation.
''It was an interesting experience. I don't think I got a club right all week. I could not trust it.
''It was nice to come out here today and have an idea where the ball was going to land. It was more praying and guessing last week.''
If he had done well at Mexico - where he had received a last minute invitation - doors could have been opened up for him.
That did not eventuate and he was always going to come back and play in the Open.
''To win a NZ Open is something I would like to have on my resume at the end of my career. I was always coming back for this. It was probably a tougher decision to go last week.''
Michael Hendry played in Mexico in 2017 and came back to Queenstown to win the Open, so it can be done.
Fox, the top ranked New Zealander in the field, said, if anything, arriving late may help him.
''Arriving on Wednesday probably decluttered my week if anything. Getting in this morning meant I had to get stuff done ... they are two golf courses I really like playing, so that is going to help me.''
He said there was a lot of top New Zealand golfers in contention and it was exciting to be playing alongside the likes of Michael Campbell.
''It would have been nice to have been here and prep properly with Steve [Williams]. But you've got to take the opportunities like I had last week.
''I still believe if I play to the level I can get to I can win. The thing for me is to manage the fatigue, manage the energy levels on the golf course.
''The golf game feels like it is in a pretty good place.''
Fox won the Super Six tournament in Perth two weeks ago, which showed he was in good form.
He missed the cut last year and will play with his father, former All Black Grant Fox, as his amateur partner. He will tee off at Millbrook today at 7.57am.
