Lawrie recorded four birdies against only one bogey in his second round, joining Martin Kaymer as the only players in the 12-man field to break 70 at the Gary Player Country Club. Kaymer matched Lawrie's 3-under 69 Friday, and at 3-under 141 he trails the Scotsman by a single shot at the midway point.
After holding a share of the lead after the first round, Bill Haas shot a 1-over 73 Friday at Sun City and sits in a third-place tie alongside Francesco Molinari, Charl Schwartzel and Louis Oosthuizen. The foursome finished 36 holes at 1-under 143, three shots behind Lawrie.
Entering as the two-time defending champion at the event, Lee Westwood matched Haas with a 1-over 73 in his second round and will begin the weekend alone in seventh place at even par, four shots off the pace.
Having shared the lead with Haas entering the second round, Belgian Nicolas Colsaerts struggled to a 6-over 78 Friday to fall back into a tie for 10th with South African Garth Mulroy, eight shots behind the leader. A week after a runner-up finish in Dubai, Justin Rose also struggled, failing to make a birdie Friday en route to a 7-over 79. At 8-over 152, the Englishman will begin Saturday's round in the inauspicious position of 12th among the 12-player field.