A field of 64 players got started Thursday at the WGC-Mexico Championship, where the leaderboard has a decidedly international flair. Here's how things look after the first day in Mexico City, as play was suspended late in the afternoon because of inclement weather with Louis Oosthuizen out to an early lead:
Leaderboard: Louis Oosthuizen (-7), Chris Paisley (-6), Xander Schauffele (-6), Shubhankar Sharma (-6), Rafael Cabrera-Bello (-5), Kiradech Aphibarnrat (-5)
What it means: There were plenty of low scores as players more often than not successfully calculated the elevation adjustments at Club de Golf Chapultepec. Paisley broke out early, followed by Bubba Watson who was 7 under through 11 holes before falling back to a 2-under 69. That created an opening for Oosthuizen, who finished T-24 at the Honda Classic and grabbed sole possession of the lead with a bogey-free 64.
Round of the day: It's remarkable to think that Oosthuizen's 2010 Open triumph remains his lone PGA Tour victory, but the veteran has a chance to add to that collection after going bogey-free in the opening round. Oosthuizen started with three birdies over his first five holes, then authored the highlight of his round when he stuffed his 239-yard approach to within 4 feet for an easy eagle on the par-5 15th.
Best of the rest: Paisley may be a relative unknown to American fans, and this constitutes his PGA Tour debut. But the Englishman has made plenty of noise this year on the European Tour, including top-5 finishes in both Abu Dhabi and Dubai, and he's again in contention after a 6-under 65. Paisley had four birdies over his first six holes and carded seven birdies before dropping his only shot of the day on No. 16.
Biggest disappointment: Justin Thomas came out on top last week at PGA National, but his bid for back-to-back victories suffered a setback when he opened with 1-over 72. Thomas made only two birdies on the day, including none over his final 12 holes, and after the round told reporters that it was "probably the worst I've felt over the ball in my life."
Biggest storyline heading into Friday: With this week's no-cut format, even players several shots off the lead aren't sweating any given deficit. That includes world No. 2 Jon Rahm, who opened with a solid 67 to sit three shots behind Oosthuizen, while Sergio Garcia and Rickie Fowler headline the group four shots back at 3 under.
Shot of the day: Defending champ Dustin Johnson nearly whipped the crowd into a frenzy on the par-3 17th, when he spun his tee shot back to within 4 inches. The birdie capped a tumultuous six-hole stretch in which Johnson played 1 under without making a single par. He ended up at 2 under, five shots back.
Quote of the day: "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