2025 Platinum
The former world number one shot a five-under-par 65 to put him ahead of Frenchman Raphael Jacquelin and Australian duo Scott Hend and Cameron Smith after the second round in Fanling.
He led by two after hitting six birdies - four in the space of five holes - though he let his standards slip with a bogey on the fourth.
Smith looked like bettering Els's round after seven birdies in his opening 10 holes but a second bogey of the day on the ninth - his last - meant he also had to settle for a 65.
Jacquelin and Hend, who is fighting to retain his European Tour card, shot 67 and 66 respectively.
Els pledged that he would not have any drinks to celebrate his birthday and successful round. But he would make room for some cake, he said.