PACIFIC PALISADES (California) • Rory McIlroy's first taste of Riviera Country Club went off without a hitch on Thursday, while any competitive advantage Jordan Spieth was supposed to have quickly vanished in the opening round of golf's Northern Trust Open.
World No. 3 McIlroy blasted his way to a four-under 67 in his tournament debut, while American Spieth, the reigning Masters and US Open champion, slumped to one of the worst rounds of his career on a course he has played more than 30 times in five previous visits.
Riviera is considered a shotmaker's course and, while four-time Major champion McIlroy had his game in high gear, Spieth did not as his 79 resulted in a 12-stroke swing between two of the sport's brightest young stars.
"It is just a day to forget and I won't think much on it," said Spieth, who shared fourth place at Riviera last year. The world No. 1 is 16 strokes behind clubhouse leader Camilo Villegas, who shot a sizzling 63.
The first round was halted because of darkness with 14 players still on the course.
Americans Chez Reavie, Bubba Watson and Luke List are tied for second after shooting 66s.
McIlroy headlines a group of seven who finished their first rounds in a tie for fifth. The 26-year-old is working hard on his pre-Masters schedule, which is why he decided to enter this week's US$6.8 million (S$9.6 million) PGA Tour event. Thursday was the first time in seven seasons he has played a round on the United States West Coast swing.
"It is always nice to come to a historic golf course," he said. "I just wanted to get a good start. I didn't want to put myself behind the eight ball early."
The Northern Irishman finished with five birdies, one bogey and 12 pars on the 7,349 yard, par-71 layout. One of his best holes of the day was the par-four seventh, where he struck his approach shot from 143 yards to three feet, setting up a birdie.
He said overnight rain had helped make the course easier to play.
"I put myself out of position sometimes but with the way the golf course was playing, it didn't punish you much," he said. "It happens a handful of times a year that we get to play a historic course like this. You got Augusta and we had it last year with Royal County Down in Ireland and you've got this course."
McIlroy dropped to No. 3 in the world this week, losing ground to Australia's Jason Day.
Spieth and McIlroy have met just twice since the American won the Tour Championship in October. The Texan finished seventh and McIlroy 11th in China and the Briton was third and Spieth fifth in Abu Dhabi.
Spieth had eight bogeys and one double bogey as he fired the worst first round of his career. He has shot in the 80s just twice - the third round of the 2013 Memorial and the third round of the 2014 Tour Championship.