Rory McIlroy fired seven birdies and one sensational eagle on the way to an eight-under par 63 and a one-shot lead over Dustin Johnson the WGC-Mexico Championship on Thursday.
Former world number one McIlroy, now ranked eighth in the world as he seeks his first win since the Arnold Palmer Invitational last March, belted a 2-iron 307 yards at Club de Golf Chapultepec's par-four first -- his 10th hole of the day.
It hit the front of the green and threatened the hole, McIlroy eventually making a six-footer for eagle.
"My 3-iron probably carries this week somewhere around 300 yards, and it was playing around 295 to the front, so I knew I needed to take a little off and hit a little cut down there," McIlroy said. "Nice to start the back nine like that."
His only miscue on the day was a bogey at the sixth, but he rebounded with a 20-foot putt for birdie at his penultimate hole, the eighth, to lead 2017 champion Johnson by one stroke.
Like all the players in the elite World Golf Championships event, McIlroy is adjusting to playing on a course situated 7,800 feet above sea level, where he said some shots could go 100 yards further than he would normally expect.
"It's fun," McIlroy said. "I'm glad we don't have to do it every week but while we're here we might as well make the most of it."
The Northern Ireland star did, hitting 17 of 18 greens in regulation and 10 of 14 fairways. He ranks third in the field in strokes-gained putting through one round.
"When you're confident with the flat stick, you're not putting yourself under pressure to hit it closer to the hole," McIlroy said. "You're not trying to take on shots that you don't really need to."
Johnson had seven birdies without a bogey in his 64 and was two shots clear of Justin Thomas and Matt Kuchar.
'Tiger, Tiger, Tiger'
Tiger Woods received a rapturous welcome from fans on the first tee, where he was introduced for his first competitive start in Mexico as "Tiger! Tiger! Tiger Woods."
"He said my name three times, right?" Woods said. "That was different."
Woods then promptly hit his tee shot out-of-bounds on the way to an opening double bogey.
He bounced back with three straight birdies at the fourth, fifth and sixth on the way to an even-par 71.
"I was trying to cut it and I pulled it across and hit it dead off the toe," he said of his opening tee shot. He did the same when he hit the second one.
"It's just not going to cut when you hit it off the toe. Didn't cut."
He finished with four birdies and two bogeys along with that double.
"I think realistically I could have gotten probably four or five (under par) out of it today," Woods said. "Just couldn't quite keep it going."
Things were much worse for defending champion Phil Mickelson. One year after edging Thomas in a playoff he opened with an eight-over par 79.