Rahm chasing Horschel at Torrey Pines

Jon Rahm fired a final-hole eagle to get within three strokes of early leader Billy Horschel after the opening round of the Farmers Insurance Open in California.

The world No 1's effort at the par-five last close a round-of-the-day 66 on the South Course, one of two courses being used at Torrey Pines, keeping him in touch with the early pacesetters.

Rahm holed a 12-footer at the first and followed a birdie at the par-five sixth by getting up and down from the greenside bunker at the ninth to pick up another shot and reach the turn in 33.

The Spaniard rolled in a 30-footer at the 11th and posted back-to-back birdies either side of bogeys at the 12th and 15th, before firing his approach at the 18th to inside 15 feet and holing the eagle putt.

"The conditions were relatively easy," Rahm said. "I hit it great off the tee, put myself in really good positions. The few times I was off, for the most part I was able to give myself a chance to save the hole, so I think that was the key.

"Nothing was really bad. I feel like everything was feeling good, everything was coming out and feeling the way it should and it showed in the score."

Horschel carded nine birdies in a bogey-free round on the North Course to hold a one-shot advantage over the chasing pack, with Michael Thompson in second spot ahead of Kevin Tway and Germany's Stephan Jaeger.

Rickie Fowler and Francesco Molinari are both in the group three off the pace alongside Rahm, having carded opening-round 66s on the North Course, while English pair Justin Rose and Aaron Rai are four behind alongside Scotland's Martin Laird.

Dustin Johnson, Justin Thomas and Xander Schauffele all opened with four-under 68s, while defending champion Patrick Reed shot an even-par 72 and is