TROON, July 15: Briton Paul Casey and in-form Frenchman Thomas Levet made the most of near-perfect conditions to share the lead in the British Open first round on Thursday.

Casey and Levet upstaged tournament favourite Ernie Els, world number one Tiger Woods and U.S. Masters champion Phil Mickelson, firing five-under-par 66s on a relatively calm day of bright sunshine at Royal Troon.

While Els (69), Woods (70), Mickelson (73) and most of the other challengers slipped backwards on Troon's treacherous second nine, Casey and Levet finished strongly.

Englishman Casey, 26, reeled off seven birdies and two bogeys to set the early pace before being caught by the 35-year-old Levet, who qualified for the Open championship by winning last week's Scottish Open at Loch Lomond.

A further stroke back on 67 was New Zealand's Michael Campbell. Els had charged into an early lead before slipping back with a late double-bogey, the South African needing two shots to escape from a bunker on the 17th green which wiped out the advantage he gained from a hole-in-one at the eighth.

The world number two, looking to lift the Claret Jug for the second time, had moved to four under with three holes to play after mixing two birdies with his ace. Champion at Muirfeld in 2002 when he beat Levet in a sudden-death playoff, he picked up his first shot at the par-five fourth before achieving his ace with a wedge at the famed Postage Stamp, the shortest hole on the British Open rota at 123 yards.

He then rolled in a 15-foot birdie putt at the par-four 11th before bunkering his tee shot at the par-three 17th on the way to a double-bogey five. "I don't feel good after that," the three-times major winner said. "I had a pretty nice round going and then pulled a five-iron left off the tee.

"I had a bit of a downhill lie in that bunker but it wasn't the most difficult lie I've had in my life. I just messed it up." Tied for fourth in the clubhouse on 68 were Britons Gary Evans and Kenneth Ferrie, South Korea's K.J. Choi, Swede Carl Pettersson, Australia's Mathew Goggin and British amateur champion Stuart Wilson.

The 35-year-old Evans, in the first group out, holed out with a five-iron approach from 227 yards for an albatross two at the par-five fourth. It was the first albatross of his career, and the first at a British Open since Briton Greg Owen on the 11th hole at Royal Lytham and St Anne's in 2001.

Rich Beem, the 2002 U.S. PGA champion, raced to the turn in five-under 31 but lost momentum on the tough back nine on his way to a 69, a score matched by seven-times European number one Colin Montgomerie.

Woods, with his status as the world's finest player under threat for the first time in almost five years, battled back from bogeys on 12 and 13 with a birdie at the par-five 16th.

He had started well, holing out from 30 feet for birdie at the par-four second before wasting a golden opportunity of getting to two under at the 210-yard fifth, where his birdie putt from five feet lipped out. The 28-year-old American also birdied six and eight but dropped another shot in between when he three-putted from 20 feet at the par-four seventh.

FIRST ROUND SCORES: