It was enough for a three-shot lead over Australia’s Cameron Smith, Americans Patrick Cantlay and Bubba Watson, and Japanese players Hideki Matsuyama and Shugo Imahira.

The bogey-free round equalled the lowest of his career.

Jet-lagged and exhausted from his past five weeks of golf that included two majors on different continents, a home appearance at the Andalucia Masters, a win at the Irish Open and a trip to a friend’s wedding, Rahm decided to cut short his practice session yesterday.

That meant he played the last nine of his first round, from the 10th, blind.

"I tried to put a little emphasis on being rested and it paid off today," Rahm, the world number eight who is seeking his third title of 2019, said.

"I have three more days to go and hopefully the battery lasts, but that was the main deal for me."

Rahm needed just 23 putts and missed just once from inside 25 feet.

"My last 10 holes, I made a lot of putts," he added.

"I hit really good putts and read the greens properly, but I think the main key out of all that, it was my positioning."

Six players are tied for seventh spot on four under, including Englishmen Ian Poulter and Tyrrell Hatton.

They are joined by Americans Andrew Putman and Nate Lashley as well as Denmark's Thorbjørn Olesen and Sweden's Alexander Noren.

World number one Brooks Koepka of the United States is on two under, while world number two-ranked compatriot Dustin Johnson is a further shot back with world number three Rory McIlroy of Northern Ireland.

England's Justin Rose, the world number four, is three under.