Els, seeking back-to-back victories after winning his first PGA Tour title in 18 months Sunday, carded a second consecutive 68 at Emirates Golf Club for an 8-under-par 136.
Els was bemoaning a number of missed opportunities on the back nine and was disgusted with his tee shot on the par-5 18th, hooking it into a tree-lined sandy waste area left of the fairway.
The South African had more than 200 yards left to reach the green with a tree partially in the way, but he smashed a four-iron shot to within 35 feet of the flag and made the putt.
"I was lucky with the lie," said the two-time U.S. Open champion. "A foot further on it would have been in a lot of footprints, but once I saw the lie I knew I had a chance. I had 213 yards to the hole and a bushy tree in front of me, but if I could miss that I had a clear view of the green.
"It was just as tough a shot to lay up, so I thought I might has well have a go and it came out perfect. But I did not get any applause and thought it was in the water.
"It really made my day. I missed quite a few putts on the back nine and that made up for everything. It's got to be in the top three best shots I've ever hit. Shots like that you only have a 30 chance of succeeding."
Wi earlier fired a hat-trick of birdies on the front nine and went one better with four in a row coming home to delight his Korean fan club.
"It's really nice," said the Los Angeles-based 30-year-old, who was befriended by a Korean club member during the week. "I guess they don't get many visitors from Korea out here so I suppose it's nice to see someone familiar to them."
Bickerton overcame a wrist injury and a disturbed night's sleep courtesy of 2-year-old son George to add a 68 to his opening 69, and could have been joint leader but for dropped shots on the last two holes.
"My wife Julie and George are here with me but he's got a bit of a chest infection and as soon he goes down to sleep he starts coughing," Bickerton said. "I was a bit ratty this morning on the first tee."
Fasth meanwhile suffered an embarrassing moment on the ninth when he split his trousers bending down to pick up his ball.
"I thought it was pretty funny, but no one laughed," said Fasth, second to David Duval in the British Open last July.
Ryder Cup captain Sam Torrance of Scotland continued to shock himself with his form in his first tournament in five months. The 48-year-old carded a 71 to stand at 5-under, four off the lead.