The South African, who won the British Open in 2002 and 2012 and the U.S. Open in 1994 and 1997, almost had a second eagle on the last hole that would have equaled a course record.
He settled for a birdie that gave him the overall lead.
“It doesn’t really mean much until Sunday. But getting into the race — so to speak — early on in the tournament is nice, to be right in the hunt,” Els said.
Els is one stroke ahead of Matthew Baldwin of England, Alex Noren of Sweden, Robert-Jan Derksen of the Netherlands, and Martin Kaymar, who delighted the home crowd by finishing in the afternoon with three successive birdies, nine in all.
“I had a lot of chances on the back nine and I pretty much made all of them,” said the German.
Baldwin and Noren both holed eight birdies in the morning, while Derksen had six, as well as an eagle.
English pair Matthew Nixon and Tom Lewis, and Alexander Levy of France are next after shooting 65s.
“Hats off, it was just everything went right, holed a lot of putts and that’s that, really,” Nixon said. “I had two eagles and my dad is always telling me I’m rubbish at par-5s so hopefully he’ll feel better about that.”
Els finished tied for fourth at the U.S. Open last week and had a share of sixth place at the Wentworth Club in his previous two tournaments.
“I’ve really been working hard at my game,” the 43-year-old said, referring to his recent fine form.
“I could feel that things were coming around a bit. I’ve had a bit of an iffy year up to now, but I really feel that my swing feels good and my body feels good, so I can swing the club properly.”
Els started at the 10th hole, and made five birdies in the outward 31.
He holed a 40-foot birdie putt on the short second, before doing brilliantly on the par-5 sixth.
Despite finding himself in the rough facing a flag guarded by water, he drove the ball almost 250 yards to within five feet of the hole, before putting for the eagle.
“It’s just a pleasure to play, not to go through a torture chamber like I did at the U.S. Open. So, a nice start,” Els said.
“I’m glad that I came (here) because I feel my game is coming around. I just haven’t had the results, so it’s nice to see where my game is.”