Wentworth - South Africa's Ernie Els gave his fellow professionals a lesson in how to play his course as he took an early lead at the PGA Championship at Wentworth on Thursday.
Els, responsible for re-designing Wentworth's course over the last three years, covered the front nine in 31 shots four-under par, four in front of his playing partner and world number one Rory McIlroy.
Scotland's Marc Warren, out in the first group, was in the clubhouse on four-under, after a round of 68, which included four birdies and an eagle.
The pair were joined on four-under by Australia's Andrew Dodt who put together a run of four birdies from the second to rush up the leader board.
Another South African George Coetzee was also going well early on lying a shot behind Els and Warren on three-under par 12 holes.
Els made his first move by birdieing the par-three second and followed up with birdies at the fourth, sixth and seventh before a run of four pars.
India's Jeev Milkha Singh joined the group on three-under after an eagle at the 12th, now a par five.
McIlroy was having a mixed morning. An eagle three at the par-five fourth moved him to one-under-par and a birdie at the seventh got him two-under the card before a disastrous run of three straight birdies saw him go to one-over.
In the same group, Northern Ireland's Graeme McDowell, who McIlroy succeeded as US Open champion, was one-under after 11 but world number three Lee Westwood, runner-up here last year, slipped to one-over after a bogey at the 380-metre 11th.
Triple-major-winner Els, 42, has won just twice on the European Tour in the last five years and despite winning seven World Match Play titles on this course has never won this tournament, the flagship event of the tour.
Two years ago he was heavily criticized by his fellow players for the way he had tinkered with the course, particularly the way he changed the par-five 18th.
Els made more modifications this year which have appeased the players, including making the 12th a par-five, and before the tournament began he was predicting a winning score of around 16-under par this week.
He was on course for that after his efforts in the opening 10 holes but Irishman Padraig Harrington, like Els a triple-major winner, had a horrific start as he was out in 39, four-over par after a triple bogey six on the par-three second.
Defending champion Luke Donald, who could displace McIlroy at the top of the world rankings this week, was an afternoon starter.