It will be recalled how McDowell holed a couple of sensational putts on the final green to overtake Woods in the final round two years ago and then beat him in the play-off. McDowell's 66 was the best round over the opening 36 holes this time round and he is now focusing on another victory in his season-ending event in a year that hasn't quite turned out as well as he would have liked.
However, the 33 year-old Irishman, who got engaged only a couple of weeks ago, was back to his very best and stands three ahead of his closest rivals Bo Van Pelt and Jim Furyk and four clear of Woods, who looked to be still some distance short of his best
Meanwhile Scotland’s Paul Lawrie is the one-shot leader at the halfway stage of the Nedbank Challenge, with his three-under-par 69 giving him the edge at Sun City.
The Ryder Cup winner takes the slenderest of advantages into the third day, with Martin Kaymer a shot behind.
Four players then trail on one under; Bill Haas, Francesco Molinari, Louis Oosthuizen and Charl Schwartzel, with two-time defending champion Lee Westwood on level par.
Behind him is Peter Hanson (one over), before a real gap to the rest, with Carl Pettersson three over, Nicolas Colsaerts and Garth Mulroy four over and finally, Justin Rose, after shooting a horrible 79, a further four shots back.
Ryder Cup hero Kaymer also carded a 69 consisting of five birdies and two bogeys, while Westwood, looking for a third successive win at the event, was left to rue a bogey and a double-bogey six at the par-four 16th as he ended one over for the day.