England's Justin Rose, twice a runner-up in the BMW PGA Championship, wasted little time in getting to the top of the leaderboard as The European Tour's flagship event got under way at Wentworth Club.
Rose, who finished joint second behind Ryder Cup team-mate Luke Donald 12 months ago and lost a play-off to Anders Hansen in 2007, went to the turn in 32 to join Finland's Mikko Ilonen on three under par.
The 32 year old saved par on the first after finding a fairway bunker off the tee and coming up short of the green with his approach, while he also got up and down from sand on the par three second.
A bogey on the third was followed by birdies at the fourth and fifth and two more birdies on the eighth and ninth - the former from 20 feet -took Rose alongside former British Amateur Champion Ilonen, who had picked up shots at the fourth, sixth and ninth.
A chilly morning saw Rory McIlroy wearing thick black gloves between shots as he teed off alongside Ryder Cup team-mates Graeme McDowell and Paul Lawrie, with the World Number Two missing two good birdie chances on the opening two holes.
McIlroy, still seeking a first win of 2013 after five victories around the world last season, birdied the third and after a bogey on the fifth picked up shots on the sixth and ninth to be two under.
Spain's Miguel Angel Jiménez, making his 600th European Tour appearance, was four off the lead on one over after 11 holes.
Ilonen, whose two European Tour wins came in 2007, briefly moved two clear of the field with birdies at the 14th and 15th, the latter from six feet after a superb approach to the 489 yard par four.
But a first bogey of the day on the 16th dropped him back to four under and one ahead of McIlroy, who had birdied the par five 12th after hitting his second shot just through the green and chipping to three feet.
Rose was a shot further back after a clumsy chip on the 13th cost him a bogey five.
Ilonen dropped a shot on the 16th after a pulled drive but birdied the 18th to card a five under par 67 that might prove a difficult target to match given the conditions.
"It was pretty nippy when we started and stayed that way," Ilonen said. "All day I was thinking 'Can I get these waterproof trousers off?' and never managed it.
"We even had hail on the ninth tee. I said to a friend last night it was going to snow today and she laughed at me. This is the British summer."
Italy's Matteo Manassero had become Ilonen's nearest challenger on four under with three to play, with Rose bouncing back from his bogey on the 13th with a birdie on the 14th, a hole McIlroy three-putted in the group behind.
Best start of the day had come from regional qualifier Jason Levermore, who fired a hole-in-one on the second with an eight iron from 155 yards.
