Jon Rahm made a flawless start in his professional debut at the Quicken Loans National as he earned a one-stroke lead after the opening round.

After finishing as the low amateur at last week's U.S. Open, Rahm could not have dreamed of a better start to life as a professional on the PGA Tour, carding a bogey-free seven-under-par 64 on Thursday.

Amid a subdued field at Congressional Country Club, Rahm did not drop a shot, holing seven birdies in Bethesda, Maryland after storms delayed the start of play for more than two hours.

The 21-year-old Spaniard, who received the silver medal at Oakmont having finished tied for 23rd, started on the back nine and birdied the 12th, 13th and 18th holes.

Rahm added another four birdies following the turn, with three of those coming from his final five holes.

Jhonattan Vegas is a stroke further back after he also posted seven birdies, though he did bogey the second hole.

Former world number one and four-time major champion Ernie Els is two shots off the lead, alongside Jamie Lovemark, Kyle Reifers, Camilo Villegas, Bill Haas, Harold Varner III, Billy Hurley III and Wesley Bryan.

Marc Lishman and Webb Simpson are a shot further back, in an 11-way tie for 11th position.

At three under is Rickie Fowler, who recorded a 68.

Defending champion Troy Merritt opened with an even-par 71.

Meanwhile, Jim Furyk struggled after finishing in a tie for second at the U.S. Open, with the veteran American ending the round two over the card.