|Northern Trust Open first-round leaderboard|
|-8 C Villegas (Col); -5 L List, C Reavie, B Watson (all US); -4 R Barnes, B Crane, C Danielson, C Howell III, J Leonard, S Stefani (all US), R McIlroy (NI), T Van Aswegen (SA). Selected others:-3 M Laird (Sco), L Donald (Eng) -2 J Donaldson (Wal), J Rose (Eng), +8 J Spieth (US)|
Rory McIlroy flourished on his first appearance at the Northern Trust Open at Riviera in California, carding a four-under opening round of 67.
The world number three, 26, had five birdies and one bogey but trails early leader Camilo Villegas by four shots.
Colombia's Villegas carded a sublime 63 but bogeyed the ninth as he fell one short of tying the course record.
Americans Chez Reavie, Bubba Watson and Luke List are on five under but Jordan Spieth shot an eight-over 79.
World number one Spieth made eight bogeys as well as a double-bogey on the 18th in the worst opening-round score of his professional career.
Scotland's Martin Laird finished with a three-under 68 alongside Englishman Luke Donald, while Wales' Jamie Donaldson and England's Justin Rose are a shot further behind.