Defending champion Lee Westwood and major winner Graeme McDowell shared the clubhouse lead in Thursday's opening round of the Malaysian Open.

Westwood, who romped to a seven-shot victory last year, again thrived at the Kuala Lumpur Golf and Country Club, mixing seven birdies with one bogey to record a six-under-par round of 66.

Former U.S. Open champion McDowell then matched that effort, also carding seven birdies on the par 72 layout, with both players' only blemish coming on the tricky par-four sixth hole.

Among early finishers, England's Tommy Fleetwood was third after a 67, two strokes ahead of European Ryder Cup captain Paul McGinley.

Canadian Richard Lee and Australia's Andrew Dodt also shot 69, while local hope Mohd Iylia Jamil had a 70.