Only a bogey on the par-four 15th hole stopped the Scot, who is four under for the tournament, registering the outright best round of the day, an honour he had to share with Martin Kaymer, who starts today's third round in =second place.
Four players follow the German on one under, Bill Haas, Francesco Molinari, Louis Oosthuizen and Charl Schwartzel. Lee Westwood, the defending champion, is on level par and Peter Hanson on one over.
Lawrie's controlled round was all the more impressive considering the wind which ripped around the course. "I played nicely," he said. "I struggled a bit with the driver, so I hit a lot of three-woods off the tees. I hit my three-wood pretty far, but I also hit a lot of good shots with my irons. The greens are a little slower and I left a few putts out there.
"The wind was swirling, and it was quite difficult. It was chopping and changing, a little bit like Augusta. It is difficult to get the distance right this week, but so far we have only got a couple wrong, so we've done okay."
In a compact field of just 12, though, Lawrie added: "The leaderboard is pretty damn packed. There is still a lot of golf to play and a lot of time for guys to come back who struggled in the first two days. So far, so good for me, but there is a long way to go."
Behind Hanson, Carl Pettersson is on three over, Nicolas Colsaerts and Garth Mulroy are on four over and, finally, Justin Rose is a further four shots back.
Yesterday was a horror day for the Englishman,with a seven-over 79 not among his finest rounds.
Kaymer's 69 included five birdies and two bogeys, while Westwood, looking for a third successive win at the event, was left to rue a bogey plus a double-bogey six at the par-four 16th as he shot one-over-par-73 .
He had little on compatriot Rose, though, who shot 79 in a round heavily undermined by a triple bogey on the par-four third. The second-worst score of the day, 78, was registered by Colsaerts.