Rahm was six-under through his first eight holes before making his only bogey before the turn and finishing with three more birdies on the back nine as he set out on his quest to win a third straight title at Clube de Campo Villa de Madrid on Thursday.

Rahm, who started on the 10th, was two shots behind clubhouse leader Ross McGowan, the Englishman who had eight birdies and an eagle in a brilliant 10-under round of 61.

Rahm also had an eagle on his front nine, at the par-5 14th hole, to lie a shot behind second-placed countryman Sebastian Garcia Rodriguez, who had only one bogey in his 62.

Spanish fans packed around the holes being played by Rahm, the U.S. Open champion and No.1 ranked golfer in the world who is back in Spain for the first time in nearly two years.

Min Woo Lee was the best of the Aussies, with an opening round of four-under 67. PHOTO: Stuart Franklin/Getty Images.

A third title would tie him with Spanish great Seve Ballesteros.

"I was very comfortable," Rahm said. "I would have signed for the eight-under before I started."

He has shot in the 60s in his last nine rounds at this event, with his highest score a 68 in the second round in 2018, when the tournament was played at a different course.

He also shot 63 in the third round in 2019 at the Clube de Campo Villa de Madrid.

Rahm is making his first start since the Ryder Cup at Whistling Straits, where he contributed three and a half points to Europe's lost cause.

Rahm's Ryder Cup teammate, Bernd Wiesberger of Austria, was in the same group and shot a 70, featuring three bogeys and four birdies.

Min Woo Lee had the best day among the Australian contingent, the Scottish Open winner shooting a four-under 67, while Jason Scrivener was level par after a 71 and Scott Hend two-over after a 73.

The Spaniard has turned into a star, transcending sports, in his home country and huge crowds are expected at the course this weekend.

Rahm said he was extra motivated to play in front of the Spanish fans again and was grateful for the unprecedented support he has received.

"When I see my face on buses and billboards I realise the impact that I've had. Little by little, I'm getting used to it," said Rahm, who lives in the United States.

"I'm very motivated. There is nothing like the support of these fans."

The tournament, which has been part of the European Tour schedule since 1972, was cancelled last year because of the coronavirus pandemic.