Jon Rahm’s rise to No.3 in the World Ranking was a swift one thanks to his stellar 2017 season internationally, one that included his first US PGA Tour victory and first two European Tour wins. He could have added a second to his PGA Tour resume just two weeks ago if not for Dustin Johnson’s incredible performance at the Sentry Tournament of Champions in Hawaii.

Yet through all that he never shot a score as low as he did on Thursday in the opening round of the CareerBuilder Challenge. The Spaniard posted a bogey-free 10-under 62 at La Quinta Country Club that featured eight birdies and an eagle, giving him the solo lead. Rahm, who opened his round with consecutive birdies, stressed the importance of a fast start.

“It’s all thanks to the start I had. I was six-under through seven holes and with a couple missed putts,” he said. “Any time you have that going for you, you get thoughts come into your head, 60, maybe 59. Adam Hadwin did it last year with worse weather than this.”

After three straight pars following his eagle-birdie-birdie stretch at the fifth, sixth and seventh holes, 59 quickly became out of reach. But he was still able to collect four birdies on the back nine, including one at the par-4 18th to finish on a high note.

“Maybe I relaxed a little too much,” he said. “I missed a couple of iron shots and had to struggle for pars. But I’m just thankful to finish the way I did with a birdie on the 18th hole, which is always great for momentum.”

Rahm will take on the more difficult Nicklaus Tournament Course on Friday with a one-stroke lead.

Three players are just one back, including reigning RSM Classic winner Austin Cook, who carded a bogey-free nine-under 63 on the Nicklaus Course. Like Rahm, the University of Arkansas alum got off to a blistering start, getting to six under through seven holes and posting a front-nine 30. When he added birdies at 10 and 11 to get to eight under on the day, the 59 watch was on for him as well, not that he knew.

“Honestly, I had no clue at how low I was. I knew I was playing good golf and just wanted to continue,” Cook said. “It never really crept into my mind all day, luckily, I think I would have probably put a little more pressure on myself, but I was just glad to put a good round in, it’s a first round and hopefully it continues.”

He was joined at nine under by Jason Kokrak and Andrew Landry, who each posted their 63s at La Quinta.

Brandon Harkins, Beau Hossler, Martin Piller and Aaron Wise sit two back after shooting eight-under 64s.

Making his 2018 debut, Phil Mickelson fired a two-under 70 at La Quinta that featured five birdies and three bogeys.