WENTWORTH, May 24, 2012 (AFP) - The pair, ranked 212th and 291st in the world respectively, shot six-under par 66s to lead the European Tour's flagship event after 18 holes and put Rory McIlory, Luke Donald and Lee Westwood in the shade.
World number two Donald was the pick of the big three with a four-under par 68, one of a host of players on that mark, as he started the defence of the title he won in a dramatic play-off against Westwood last year.
Third-ranked Westwood started with a 70, two-under, which included a double bogey on the par-4 3rd.
World number one McIlroy had a torrid time handing in a 74 after hitting his ball out of bounds with his second shot to the par-5 12th.
The frustrated Irishman hurled his club to the ground when his fourth shot found a bunker, but he managed to escape with a bogey although his mood did not improve when he double bogeyed the 16th.
Wales' Jamie Donaldson finished with a 67, one off the lead, in a tie for third place with England's Justin Rose, Swedish duo Niclas Fasth and Richard S Johnson and Alvaro Quiros of Spain.
Drysdale's 66 included a miracle shot to the last when his approach, hit with a hybrid, bounced in the water at the front of the green and bounced back out again landing around 30cm on dry land opposite the putting surface.
The Scot thought the ball was sunk until he was alerted by playing partner Damien McGrane and calmly got up and down over the water hazard to claim an unlikely birdie.
"You could hit a thousand balls into that water and it is never going to bounce out. I don't know how it came out," said Drysdale.
"It was incredible. I was trying to cut my second shot but I pulled it and it landed in the water and came out. I was a fantastic bit of luck. It was the total opposite of the shot I was trying to hit so I was pretty disappointed. I didn't play that well over the last four or five holes but I managed to get away with it."
Lawrie did not have a bogey on his card and was five-under at the turn before making a solitary birdie, at the par-4 11th on the way home.
Lawrie said: "The key to success was not making bogeys and hitting a lot of fairways and greens. I missed a couple of chances coming in. I left a few short but I am happy with a 66."
Graeme McDowell's round was ruined by a two-stroke penalty on the 18th when the Irishman made his ball move as he approached it in the trees even though he was six feet away.
He finished with a 74 but could have saved himself a shot if he had called for the referee's assistance earlier and replaced the ball before playing it.
"I'm not sure what I could have done, but I felt something was wrong - the whole area felt like it was just kind of bouncing," said McDowell.
"How are you supposed to attempt to place the ball when you're not sure it's moved in the first place? It's just a harsh one - one of those freak scenarios in golf.
"It's my fault. I probably should have called in a referee. I've cost myself a shot there by getting a little careless.
"Once the ref is there we are protected because we can't do anything wrong at that point - even if he gives you a wrong ruling it's correct because he's told you to do it."
Leading scores after the first round of the European Tour PGA Championship at Wentworth on Thursday (par 72):
66 - David Drysdale (SCO), Peter Lawrie (IRL)
67 - Jamie Donaldson (WAL), Justin Rose (ENG), Alvaro Quiros (ESP), Richard S Johnson (SWE), Niclas Fasth (SWE)
68 - Francesco Molinari (ITA), Marc Warren (SCO), George Coetzee (RSA), Robert Rock (ENG), Ernie Els (RSA) Kenneth Ferrie (ENG), Bernd Weisberger (AUT), Scott Jamieson (SCO), Mark Haastrup (DEN), James Morrison (ENG), Rafa Cabrera-Bello (ESP), Luke Donald (ENG), Peter Hedblom (SWE)
69 - Federico Colombo (ITA), Andrew Dodt (AUS), Richie Ramsay (SCO), Paul Lawrie (SCO), Pablo Martin (ESP), Branden Grace (RSA), Charl Schwartzel (RSA), Edoardo Molinari (ITA), SSP Chowrasia (IND), Steve Webster (ENG), Colin Montgomerie (SCO), Danny Willett (ENG)
70 - Jeev Mikha Singh (IND), Jose Maria Olazabal (ESP), Lee Westwood (ENG), Victor Dubuisson (FRA), Alexander Noren (SWE), Pablo Larrazabal (ESP), Gareth Maybin (NIR), Tom Lewis (ENG), Thomas Levet (FRA), Ben Curtis (USA), Soren Kjeldsen (DEN), Fredrik Andersson Hed (SWE), Brett Rumford (AUS), David Higgins (IRL), Keith Horne (RSA)
Selected others
71 - Ian Poulter (ENG), Garth Mulroy (RSA), James Kingston (RSA), Thongchai Jaidee (THA), Martin Kaymer (GER), Darren Clarke (NIR), Miguel Angel Jimenez (ESP), Richard Sterne (RSA)
72 - Matthew Zions (AUS), Jbe Kruger (RSA), Richard Green (AUS)
73 - Thomas Aiken (RSA), Retief Goosen (RSA), Hennie Otto (RSA)
74 - Graeme McDowell (NIR), Rory McIlroy (NIR), Matteo Manassero (ITA)
75 - Marcus Fraser (AUS)
76 - Padriag Harrington (IRL)
77 - Jaco Van Zyl (RSA)
78 - Paul Casey (ENG)