GULLANE, Scotland: Denmark’s Thorbjorn Olesen hit a seven under par 63 at the Scottish Open on Thursday as top stars focused on preparing for next week’s Open Championship at St. Andrews.

Olesen claimed the early clubhouse lead on the Gullane composite links course in East Lothian, hosting the tournament for the first time.

In with 65s were American world number 12 Jimmy Walker, Adrian Otaegui of Spain and Matthew Nixon of England

Matt Kuchar and Rickie Fowler, two other members of a strong US contingent fine-tuning their links play ahead of St. Andrews, both signed for 66s, the same as former US Open champion Graeme McDowell.

Scotland’s Russell Knox, a last-minute callup for the injured world number one Rory McIlroy had a 67.

Olesen is slowly battling his way back to form after three months on the sidelines due to surgery on a hand injury.

“It’s been a tough time but I keep working on the right things and hopefully it will come,” said the Dane, who lost a play-off for the Mauritius Open in May.

“I showed today I can still shoot low rounds. I hit almost every green — only missing the 18th — and hit a lot of fairways and greens today, which was the key.”

McDowell’s opening 66 included a superb 30 on the front nine and came as a welcome return to form for the Northern Irishman who has struggled for form all year.

He missed the cut last week at the French Open, a tournament he had won in the two previous years, and he pledged after that to get the clutter out of his mind and get back to the basics.

His round could have been even better but for bogeys on the final two holes.

If low scores were out there to be had, that was not the case for former Open champion David Duval.

The veteran American suffered a nightmare start, taking a quadruple-bogey eight on the 390-yard opening hole.

Defending champion Justin Rose, the top-ranked player in the tournament following the withdrawal of McIlroy, had an early afternoon tee-time playing alongside 2013 winner Phil Mickelson and in-form Scot Marc Warren.

Away from the course, there was more talk of McIlroy’s injury woes, a ruptured ankle ligament sustained while playing football with friends ruling him out of a hotly-anticipated St. Andrews showdown with young American rival Jordan Spieth.

Close friend Fowler, who finished joint runner-up to McIlroy a year ago at Hoylake, expressed his disappointment at the news.

“I thought reading the extent of Rory’s injury it would be pretty tough for him to be fit enough by next Thursday so it’s a big blow he’s had to withdraw,” the American said.

“It’s a bummer but it’s best Rory get himself back to 100 percent health and in the bigger picture that is the most important thing.

“But in saying that you can’t live life too cautiously though it will be tough for Rory having to watch it now on TV.”