Italian Molinari meanwhile put together a remarkable run of seven birdies in eight holes between the seventh and the 14th on his way to firing a seven-under 65.
The 2018 Open champion, now ranked 418th in the world rankings, posted one further birdie in his round, with a solitary bogey at the 12th the only blemish on his scorecard, to lead by two from Swede Mikael Lindberg.
It was 43-year-old Molinari’s lowest round on the DP World Tour since January 2024.
“It’s been a long time. I’ve changed everything and then I’ve changed back,” said the 2018 Ryder Cup winner, who has not won a professional title since the Arnold Palmer Invitational seven years ago.
“Not super unexpected but I wasn’t expecting a score like that. Last week I felt very rusty, so I was hoping it would be very good prep for this week.”
Lindberg’s opening 67 included an eagle three at the third.
Switzerland’s Joel Girrbach and South African JC Ritchie are one shot further back, with last week’s Dubai Invitational winner, Manuel Elvira, among a group of players tied for fifth on three under, which also includes American Patrick Reed.
Having his first competitive outing of the year, defending champion, England’s Tyrrell Hatton, is one of seven players on two under, along with Ireland’s Shane Lowry.
Lowry recorded five birdies and three bogeys as he began his bid to bounce back from an agonising conclusion to last week’s tournament at Dubai Creek Resort.
A double-bogey at the last cost him the opportunity to potentially win the title on that occasion.
Like his playing partner McIlroy, world number three Tommy Fleetwood has ground to make up after posting a 73.
