"There's so much golf to be played. If you fall out of the lead, if you're not leading after three rounds, it doesn't really mean much at all late Sunday," Els said. "So you just want to stay in the race and keep trying to go forward."
He was followed by Matthew Baldwin of England (69) and Alexander Levy of France (68). Defending champion Danny Willett of England shot a 65 for the day's best round and was tied for fourth place with Bernd Wiesberger of Austria.
Willett was six strokes off the pace after an opening 69 and is happy he is back in contention to become the first player to defend the title in the 25th year of the event.
"Yesterday was a bit hit and miss, a little bit shaky," said Willett, whose season was disrupted by a back injury. "I haven't played a lot of tournament golf in the past 14 weeks, so it was a bit rusty. And today I hit some proper golf shots again and I played really nicely."
Five players 2008 winner Martin Kaymer and Marcel Siem of Germany, Tommy Fleetwood of England, Spain's Miguel Angel Jimenez and Sweden's Alex Noren were three strokes off the pace in sixth.