Still battling jet-lag, the reigning Masters champion had to endure a 4am wake-up call to ensure he was at Royal Melbourne in plenty of time for his 7.05am (AEDT) opening-round tee-off on Thursday.

It says plenty about McIlroy's enduring popularity - and that of his playing partners Adam Scott and Min Woo Lee - that they were greeted on the opening tee by a gallery already numbering several thousands and which only grew throughout the morning.

Presumably there will be even more following the triumvirate around the RM composite course on Friday afternoon.

All things considered, McIlroy did pretty well to sign for an opening one-over 72 after a rollercoaster day where he mixed five birdies with six bogeys.

Australian young gun Elvis Smylie, Kiwi Ryan Fox and Mexican Carlos Ortiz shared the opening-round lead at six-under 65.

They were two shots clear of Denmark's Rasmus Neergaard-Petersen, Frenchman Clement Charmasson and Scotland's Cameron Adam.

"It just goes to show how much I've learnt over on the DP World Tour, week in, week out," said Smylie, who has enjoyed a stellar 12 months after his breakthrough victory at the 2024 Australian PGA at Royal Queensland.

"You're always adjusting and adapting as the courses and climates are so different, so you're constantly adding tools to your toolbox." 

"I embrace days like today. I think I belong, and I know that and I believe that and I'm just happy that I'm able to showcase that on a stage like this."

Smylie was the only Australian in the top six after the opening round.

Ortiz stormed home to claim a share of the first-round lead after becoming one of only two players to eagle the par-5 17th on Thursday.

Scott and Lee were tied for 12th after carding 69s.

Having signed up to play the 2025 and 2026 Australian Opens on a multi-million-dollar deal, hopes are high McIlroy can surge into contention over the remaining three days.

"I felt like I could have shot under par or something in the 60s, but it doesn't look like anyone is going to get too far away today," said the 36-year-old after his opening round.

"I limited the damage and hopefully the conditions are a little better over the next few days and I can make a run."