MACAU, October 18, 2013 (AFP) - The four-time Major champion struck nine birdies against three bogeys for a two-day total of six-under-par 136.
Siddikur struck 66 in his round which included three birdies over his closing four holes, a running total of 135, in his bid to win a second Asian Tour tournament.
Els said he was disappointed to miss a two-foot birdie chance at the last hole which would have resulted in a tie with Siddikur for the lead.
"The one little putt I missed at the last will sting a little bit. I was looking at the board and it would have been perfect if I could have been seven under to be in the last group.
"But it's fine. I played really nice. I actually made some good putts and hit the ball nicely," he said.
Siddikur, the first Bangladeshi to win on the Asian Tour in 2010, is confident about his form going into the next round.
"I finished third here last year and I had good thoughts coming back. I'm hitting it good. I'm in good shape," he said.
He is also eyeing a dream showdown with Els.
"Ernie (Els) is my idol. I've been waiting for a long time to play with him. Last few years, I've missed by a few groups playing with him so hopefully this week," he said.
Scores after round 2 of the Venetian Macau Open 2013 being played at the par 71, 6606 Yards Macau GCC course:
135 - Mohammad Siddikur (BAN)
136 - Baek Seuk-hyun (KOR), Elmer Salvador (PHI), Ben Campbell (NZL), Ernie Els (RSA)
137 - Jay Bayron (PHI), Scott Barr (AUS), Daisuke Kataoka (JPN)
138 - Scott Hend (AUS)