MEXICO CITY • A late eagle propelled smooth-swinging Louis Oosthuizen to the first-round lead as a diverse mix of players lined up close behind the South African at the WGC-Mexico Championship on Thursday.

The former British Open champion offered a timely reminder that on his day, he is still among the game's elite as he carded a bogey-free seven-under 64 at Club de Golf Chapultepec in Mexico City.

He headed American Xander Schauffele, India's Shubhankar Sharma and Chris Paisley of England by a stroke while defending champion Dustin Johnson hit a 69 that included a near ace at the 17th.

In just his second PGA Tour start of the year, Oosthuizen ran off five birdies before landing an eagle at the par-five 15th, which plays more as a long par-four in the rarefied air more than 2,225m above sea level.

"I'm very confident with my driver at the moment. I've got a nice little cut going, and it's nice to be able to just aim left and swing away," Oosthuizen told Golf Channel. "I've been swinging it pretty good the last two or three weeks."

He said he had misjudged the distances of some of his iron shots, but not enough to cost him a bogey.

"You can get one with a short iron and then the next hole you come up short. It's all about the ball flight."

A runaway seven-shot winner at St Andrews in 2010, and a play-off loser in two other Majors, the laid-back Oosthuizen is rarely happier than when driving his tractor on the family farm back home.

Golf takes precedence at this time of the year, though, as the sport's elite hone their games for the Masters next month.

If Oosthuizen's lead was no surprise, Paisley's lofty position perhaps was unexpected.

"To shoot a great score against the world's best players, I'm delighted," he said.

REUTERS

WGC MEXICO C'SHIP
Day 3: StarHub Ch204, tomorrow, 1am