Jordan Spieth has admitted that it was a day to forget as he made a disastrous start to The Barclays at Plainfield Country Club.

Entering an event as world number one for the first time, the spotlight was on Spieth in New Jersey but he slipped to a four-over-par 74 to finish the day nine shots off the pace, and the 22-year-old concedes that it was one of his worst performances in recent memory.

"After the tee shots, that is the worst round I've played in years," Spieth told reporters. "It was really a very unique round for this year. I hit my first 11 fairways today and that's really hard to do out here.

"I'll do what I've done best and bounce back and I'll come back tomorrow strong. I'm not a fan of the course but I've also won on course that I didn't think fit me very well so I still know I can still shoot a low round.

"I played the front nine in two under and should have really been four or five. Typically when I hit the fairways, I'm not over par. That's what was weird about the round."

Bubba Watson is one of four players on five-under after day one.