Jim Furyk created some sparks of his own.
Furyk parlayed great iron play into 6-under 66 in the second round and took a four-shot lead over Henrik Stenson, collecting six birdies in another flawless round and reaching 10-under-par 134 for the tournament.
The defending champion, Furyk has produced 36 holes of bogey-free golf at the Gary Player Country Club, where he chipped in for birdie to win a four-way playoff last year.
Before a lightning storm set in Friday afternoon, the steady Furyk made five birdies -- all on holes he parred during the first round -- and held a three-shot lead when players retired to the clubhouse.
The weather delay lasted nearly three hours.
When he returned to the course, Furyk birdied the par-4 14th for the second straight day and moved to 10 under. He ended the day leading all 12 players in putting and also ranked first in greens in regulation.
Furyk's job was made easier by the unsteady performance of some of the other players, including Stenson, who opened with a 67 on Thursday but was just 1-under 71 in the second round.
Stenson is alone in second place at 6-under 138.
Charl Schwartzel was tied for second place with Stenson when the storm hit, but he bogeyed the 17th after the delay. Schwartzel shot a 3-under 69 and is tied for third place with Ernie Els at 5-under 139.
Els fired a 67 and rebounded nicely from a disastrous finish to the first round, when the tournament's all-time money leader went 4-over during a three-hole stretch from the 14th.
Padraig Harrington also bogeyed a hole following the re-start and shot a 1-under 71. He shares fifth place with Retief Goosen (70) and Trevor Immelman (69) at 4-under 140.
David Howell, who shared third place with Harrington after the first round, was done in Friday by two bogeys and a triple-bogey.
Howell shot a 1-over 73 and was alone in eighth place at 2-under 142. Jose Maria Olazabal also had a 73 and was two shots further back at 144.
Sergio Garcia shot a 76 and was ninth at 4-over 148. Chris DiMarco had a 75 and was a shot further back at 149. Colin Montgomerie remained in last place following a 77 and fell to 8-over 152.
The players are competing for a lucrative offseason purse, which includes a first-place prize of $1.2 million.