However, the world No 41 bounced straight back with another birdie at the only other par five to move back to six-under. Ortiz was also playing in the afternoon, a few groups behind Fox and joined the lead with an eagle at the 17th to go with six birdies and two bogeys.
Fox will have an early tee time in round two, at 7.05am local time (9.05am NZT), when he will look to set the mark for the chasers in the afternoon groups.
Smylie started the day with a bogey but went seven-under for the rest of his round to also card a 65. The 23-year-old has one DP World Tour win to his name, last year’s Australian PGA Championship.
Daniel Hillier continued his fine form, backing up a top-five finish in Brisbane last week with an opening round 68, including a close eagle look at the 14th that didn’t drop. Hillier had five birdies across the day but a double bogey at the 10th brought him back to even after a strong start before he got hot again on the back nine and moved into the top five eventually finishing in a share of seventh.
No Kiwi has ever won the event, which has some of the biggest names in golf on the Stonehaven Cup, including Jack Nicklaus, Arnold Palmer, Gary Player, Tom Watson, Greg Norman, Jordan Spieth and McIlroy,
The Masters champion was among the early groups, playing alongside Adam Scott and Min Woo Lee. The world No 2 began his day with a birdie at the 10th but followed that up with back-to-back bogeys. It was an up-and-down round for McIlroy who finished with five birdies and six bogeys to card a one-over 72. Scott and Lee finished at two-under.
Nick Voke carded an even par round of 71 after his third-placing last week while fellow Kiwis Tyler Hodge (72), Kerry Mountcastle (72), Josh Geary (73) and Kazuma Kobori (75) all finished over the card.