Defending champion Rory McIlroy fired an opening five-under-par 66 which put him one off the early pace at the CJ Cup in South Carolina.

McIlroy carded three successive birdies from the fourth and produced two more on his second nine.

Victory this week could see McIlroy regain the world number one spot.

McIlroy will move to the summit of the rankings for the first time since July 2020 if he triumphs and current number one Scottie Scheffler finishes worse than a two-way tie for second.

The four-time major winner – who has occupied the world number spot during eight previous stretches – can also overhaul the Masters champion with outright second place if Scheffler is outside the top 35.

At the end on day one, Scheffler was sharing 44th spot in the 78-strong no-cut field after carding a level-par 71.

McIlroy, 33, won last year’s event at The Summit Club in Las Vegas but the 2022 event is being played at Congaree Golf Club and Thursday was his first competitive round at the South Carolina venue.

“I was still in two minds about what clubs to hit off tees and lines but after playing it today, hopefully I’ll be a little more comfortable over the next three days,” said McIlroy, whose round was highlighted by him driving the 352-yard 15th which set up his final birdie of the day.

The world number two was sharing third place with in-form South Korean talent Tom Kim, American trio Wyndham Clark, Aaron Wise and Kurt Kitayama plus Australia’s Cam Davis.

Ireland’s Seamus Power was among a group on 67 which also included England’s Tyrrell Hatton and Norway’s Viktor Hovland while another Irishman Shane Lowry was in a large group that carded rounds of 68.

Jon Rahm and Danny Willett both completed two-under-par 69s with US Open champion Matt Fitzpatrick having to be content with a 70.