Rory McIlroy and Padraig Harrington were well outside the cut mark after difficult second rounds at the Genesis Invitational in California where Sam Burns leads the way on five-under par.
McIlroy made a steady start to his second round when looking to improve on his opening 73, but things starting to unravel when he made a double bogey on eight. A birdie on 13 was the only bright spot on the inward nine, with bogeys on 12, 14, 17 and 18 to finish with a 75 to miss the cut by seven shots.
A further two shots back was compatriot Harrington, who carded a 76 to add to a 75 as he ended on nine over.
Overnight leader Burns pulled further clear with a five-under 66.
After a first round of 64, Burns repeated the dose with a superb, bogey-free second round, birdieing two of his first three holes in a three-under first nine, before two more birdies coming home.
At 12-under, he led by five shots from a group of three fellow Americans in Tyler McCumber, Jason Kokrak and world No 1 Dustin Johnson, who moved steadily up the leaderboard with a four-under 67, claiming five birdies after his sole bogey on the second.