Doha, Qatar (My Sportsbook) - Henrik Stenson, Miguel Angel Jimenez and Andrew Coltart each shot a six-under 66 on Thursday to share the first-round lead at the European Tour's Qatar Masters.

But their advantage was a tenuous one.

Lee Westwood, Robert Dinwiddie, Anders Hansen, Louis Oosthuizen and Brett Rumford were all just one shot off the lead at five-under 67 on a tight leaderboard at Doha Golf Club.

Top players Aaron Baddeley (68), Robert Karlsson (68), Retief Goosen (69), Ernie Els (70), Sergio Garcia (70) and Colin Montgomerie (71) were also among the 50 players who stood within five shots of the co-leaders.

Stenson made it into the clubhouse first with a 66 after starting his round in an early tee time on No. 10. An opening birdie at his first hole was canceled out by a bogey at No. 11, but it marked the 32-year-old's only dropped shot of the day.

He went on to make six more birdies the rest of the way, collecting back-to- back birdies twice -- at the 15th and 16th holes, and at his final two holes on the front nine.

Stenson is looking to continue a strong run in Middle East tournaments that includes a victory at this event in 2006 and a win at the 2007 Dubai Desert Classic. He has also finished runner-up twice in Qatar, including last year to Adam Scott.

"It's a course I really enjoy playing," said the world No. 11. "I think it's [my] ninth time coming to Qatar, so I have a fair idea how to play the course."

Coltart, like Stenson, also began his round on the back nine. He made his first birdie at No. 12, then collected an eagle at the par-four 16th, where he drove the green. He made back-to-back birdies at Nos. 18 and 1.

The 38-year-old Scotsman reached six-under with a birdie at No. 4 -- joining the clubhouse leader Stenson for the first time -- but he gave that shot back with a three-putt bogey at the sixth hole. Coltart re-gained his share of the lead with a closing birdie at his last hole, No. 9.

Now ranked 759th in the world, Coltart picked up his first career win at the 1998 Qatar Masters.

"I have good memories in Qatar. I have managed to make the odd birdie around this course, but I have also had the odd disaster when it has been pretty windy," he said. "The eagle at 16 was the highlight."

Jimenez, the only co-leader who started his round on the front nine, opened with a birdie at No. 1. The 45-year-old Spaniard made three straight birdies from the seventh, then finished his bogey-free round with two birdies and seven pars on the back nine to make it a three-way tie at the top.