MEXICO CITY • Ranked No. 1 for the first time since 2015, Rory McIlroy is relishing the feeling of being on top of the world.
It was therefore no surprise that the Northern Irishman loves playing on a golf course which sits more than 2,300m above sea level.
He was in control of all facets of his game as he charged into the first-round lead with a six-under 65 at the WGC-Mexico Championship on Thursday.
He smashed his drives prodigious distances in the thin Mexico City air and complemented his long game with precise putting in earning a two-shot advantage over Americans Justin Thomas and Bubba Watson.
"I like this place, like the golf course, and have always played well at altitude for whatever reason that is," the four-time Major champion said after capping his day with a 10-foot birdie putt at the last hole.
He won the World Golf Championships (WGC) tournament in Shanghai in November and victory this week would see him complete the set of all four WGC events.
The only player to have won the Grand Slam is Dustin Johnson, who relegated McIlroy to second at Chapultepec last year.
McIlroy has been in stellar form early in the new PGA Tour season, with a tie for fifth at the Genesis Open last Sunday his worst result in four starts.
Accuracy from the tee is crucial at the tree-lined Club de Golf Chapultepec but he did not hold back on Thursday, hitting three drives of more than 365 yards.
But it was the 30-year-old's putting that pleased him most a week after an ill-fated experiment with an 89cm model that was slightly longer than his usual putter.
"Once I got out there (last week), that inch difference with the putter moves your eye line and you stop seeing your lines the way you usually do," he said.
"I saw the tournament through with it. It didn't work quite the way I wanted so... happy to have old faithful back in the bag and it worked well today.
"It was definitely validation to going back to the putter I'd been using for the last 14 months.
"If I keep putting like that, I'll be very happy."
Nipping at his heels, Thomas and Watson both mixed five birdies with one bogey in shooting 67s as they bounced back from missing the cut last week.
"I've had two 62s here, and you can get it going," said Thomas, already a two-time winner on Tour this season. "I felt like today was tough. I've never played this place with this kind of wind."
Two-time Masters champion Watson, who enjoyed a round with pop star Justin Bieber last weekend after missing the cut, had better luck on the greens.
He said: "I just made some putts today. The only thing that was missing last week when I missed the cut was I didn't make any putts."
At the other end of the field, title holder Johnson ran up four bogeys and a double in a 76 that left him equal 62nd in the 72-man field.
AGENCE FRANCE-PRESSE, REUTERS