SUN CITY, South Africa -- Graeme McDowell recovered from a double-bogey 7 at No. 14 to birdie two of his last three holes Friday for a 5-under 67 and a one-shot lead after the second round of the Nedbank Golf Challenge.
The Northern Irishman moved to 7 under for the tournament and ahead of four players who shared second at Sun City.
American Jason Dufner had four birdies in his 68 to go to 6 under in his Nedbank debut. Robert Karlsson (69), Martin Kaymer (68) and defending champion Lee Westwood (70) were also one off the lead with Dufner.
Top-ranked Luke Donald was tied for eighth at 3 under with his 1-under 71 after he bogeyed two of his first four holes in an inconsistent round that included four birdies and three bogeys.
Charl Schwartzel, who shared the overnight lead with Westwood, slipped to 10th in the 12-man field with a 2-over 74 at Gary Player Country Club to go to 2 under in the $5 million invitational tournament.
Going for the $1.25 million winner's prize, McDowell had seven birdies alongside his double bogey at No. 14, with five of those birdies coming on the back nine.
He picked up shots at Nos. 10 and 11, chipped in for another birdie at No. 13, then pushed his tee shot into the left rough on No. 14. He took two strokes to get back onto the fairway after hitting a rock -- and not his ball -- with his second. He then sent his fourth into a greenside bunker and missed a 6-foot bogey putt.
But McDowell pulled shots back at Nos. 16 and 18 for his one-stroke lead heading into the weekend.
"It was a very calm and quiet front nine and a pretty exciting back nine, I guess," he said. "I made a couple of nice birdies around the turn, a nice chip-in at No. 13 and at 14 ... that second shot can only be described as an air shot.
"There's so much trouble lurking at this golf course, (but) a better day at the office. I enjoyed that."
Dufner's 68 included two birdies around the turn. The birdie at the tough, par-4 No. 17 lifted him to a tie for second on his first visit to Sun City and first trip to South Africa.
"I did everything pretty well," Dufner said. "Obviously to play a round with no bogeys is gonna help a lot. I'm learning this golf course quickly and a little bit on the fly."
Karlsson had a second straight 69 with three birdies, no bogeys and a crucial par save at No. 8 where he made a 60-foot putt from the edge of the green.
No. 4-ranked Kaymer had three birdies and an eagle on No. 10 to be one off the lead, while No. 3-ranked Westwood had four birdies and two bogeys for a 2-under 70.
South Korea's Kyung-tae Kim put his approach to 2 feet as he birdied his first. But he bogeyed No. 2 to set the tone for an up-and-down 70 with an eagle, four birdies and four bogeys. Kim shared sixth with Englishman Simon Dyson (70).
Donald birdied No. 2 with a smooth 15-foot putt, but then bogeyed Nos. 3 and 4 on his way to 1 under for the round and 3 under overall alongside Anders Hansen.
Schwartzel had a nice save on No. 6 after pulling a tee shot into the bush. His second, crouching under a tree with a restricted backlift, found the middle of the green and he made par.
But the effort failed to inspire the Masters champion, who double-bogeyed No. 8, holed his only birdie on No. 9 and dropped another shot at No. 13.
Darren Clarke's back nine was even more dramatic than McDowell's, his compatriot from Northern Ireland.
Clarke reeled off six birdies, including four in a row from No. 12, but also had a bogey and two double-bogeys to go without a par in his last nine for a 3-under 69 and 1 under overall.