MIAMI (AFP) — World No. 1 Jon Rahm started fast and finished strong on the way to a seven-under-par 65 on Thursday and a two-stroke lead in the US PGA Tour Arnold Palmer Invitational.

Rahm, playing the tournament at Bay Hill in Orlando, Florida, for just the second time, launched his round with three straight birdies and closed it by picking up four strokes in his last three holes with an eagle and two birdies.

Rahm, who regained the world number one ranking with his third PGA Tour title of 2023 at Riviera last month, was two shots clear of Americans Chris Kirk, Cameron Young, and Kurt Kitayama.

"I took advantage of the good swings," Rahm said. "I put myself in a really good spot on one off the tee. Took advantage with a wedge in my hand.

"I can say the two shots on two and 17, to have a combined six feet in those two holes, it just doesn't happen. I hit two really good shots and landed in a very precise spot."

Kirk is coming off his first victory in almost eight years at the Honda Classic on Sunday.

It was his fifth US PGA Tour title but his first since he took a break from the tour in 2019 to deal with depression and alcohol misuse.

Young, last season's rookie of the year who also made bogey there, said there was no secret to the trouble caused by the ninth.

"It's 500 yards into the wind with the narrow fairway and four and a half inch rough," said Young, whose five-under effort included a chip-in for eagle at the 12th along with five birdies and a pair of bogeys.

"It's just a really hard hole," he added saying the par-four was "just basically a par-five."

Kitayama was bogey-free with six birdies through 16 holes, but he bogeyed the ninth to fall back into the group at five under.

World number two Scottie Scheffler, who has a chance to regain the top spot from Rahm this week, headed a group of eight players on 68 that also included Jordan Spieth and Patrick Cantlay.

Rory McIlroy, the 2018 champion at Bay Hill who could also return to number one this week, opened with a one-over par 73 that included a double-bogey at the par-five sixth, where he was in the water off the tee.