(CNN -- Scotland's Paul Lawrie, whose 10-year European Tour exemption for winning The British Open ends this season, leads the Johnnie Walker Championship at Gleneagles after the opening day.
Lawrie carded a five-under-par 67 to lead the Johnnie Walker Championship after the opening round.
Lawrie, 97th on the money list and needing to be in the top 115 in November to save his Tour card, scored a five-under-par 67 as he began his latest bid for a first victory since the 2002 Wales Open.
The 40-year-old, still Britain's last winner of a major title, goes into the second round one stroke ahead of a group of four players which includes his fellow-Scot Steven O'Hara and defending champion Gregory Havret.
However, it was a bad day for both Colin Montgomerie and Thomas Bjorn. Ryder Cup captain Montgomerie lost two balls as he slumped to a 76 -- and could now miss a fourth successive cut for the first time in his European Tour career -- while Bjorn crashed to an 82.
This is the Dane's first event since the start of last month. He has been suffering from dizziness and extreme fatigue and even underwent a brain scan during his lay-off.
Montgomerie, who is without a top-10 finish for 14 months, told reporters: "I didn't play well, obviously.
"I haven't been playing well all year, and it just continues. I have lost a bit of confidence -- obviously you do when you miss cuts and you don't compete, never mind contend."
Lawrie did not drop a stroke all day with the highlight a 40-foot putt for an eagle on the long ninth.
Havret, the leader from start to finish last year, and O'Hara, who became a father three weeks ago, share second place with Swede Ake Nilsson and Australian Wade Ormsby, who reached seven-under before double-bogeying the short 17th and dropping another on the last.
Oliver Wilson and Soren Hansen, back on the course where they clinched Ryder Cup debuts a year ago and the two highest-ranked players in the field at 44th and 49th in the world, shot 73 and 69 respectively.
Teenage New Zealander Danny Lee, who in Australia in February became the Tour's youngest-ever winner, had an eventful 71.
Three-over after six holes of his first event in Europe since his win, Lee played the next five in six-under, matching Lawrie's eagle on the ninth, but then had two more bogeys.
He still out-scored the circuit's two other amateur winners. Irish Open champion Shane Lowry returned a 74 and Spaniard Pablo Martin, winner of the Portuguese Open two years ago, a 72.
Meanwhile, Germany's Martin Kaymer has been ruled out of action for at least six weeks after sustaining a foot injury when go-karting in America which will require surgery.
"Obviously this is a very unfortunate situation, but I have a top medical team around me which will provide the best treatment to get me back to the competition," the 24-year-old Race to Dubai money leader told the European Tour Web site.
"I will do everything to recover as soon as possible." Kaymer won the French and Scottish Opens back-to-back last month.