Grayson Murray fired a seven-under-par 65 to grab a share of the lead at the US PGA Tour's Puerto Rico Open on Saturday.

The 27-year-old from North Carolina bounced back from a bogey on the 17th to finish with a birdie on the last to join local hope Rafael Campos at the top of the leaderboard on 14 under heading into Sunday's final round.

Murray's closing birdie capped a sparkling round which erupted early on with four birdies and three pars in his first seven holes at the Grand Reserve Golf Club in Rio Grande.

A 10-foot birdie put on the ninth took him to five under for the round before two more birdies on the 12th and 14th pushed him into the lead.

A bogey on the 17th threatened to sour his round, but Murray recovered to birdie the par-five 18th to ensure a share of the lead alongside Campos.

Grayson Murray sets up a birdie on the 18th to take a share of the lead at the Puerto Rico Open
Grayson Murray sets up a birdie on the 18th to take a share of the lead at the Puerto Rico Open GETTY IMAGES NORTH AMERICA / ANDY LYONS

Campos meanwhile -- ranked 666th in the world -- put himself in the frame for a fairytale first tour victory with a five-under-par 67.

The 32-year-old made his PGA Tour debut at the Puerto Rico Open as an amateur in 2008 and has posted two top-10 finishes at the event in the years since.

He looked set for a bogey-free round on Saturday after reeling off six birdies and 11 pars, before a bogey on the last dropped him back to five under for the day, 14 under overall.

Campos and Murray lead by one shot from Australia's Cameron Percy and South African Branden Grace, who are at 13 under.

Percy moved up the leaderboard with a five-under-par 67 while Grace carded a 68 for a second straight day.

Overnight leader Brandon Wu meanwhile fell away with a one-under-par 71. Wu is two of the lead on 12 under alongside Argentina's Nelson Ledesma and Andrew Putnam.