He followed his opening 62 -- one shy of compatriot Ernie Els' superb course record -- with a two-under 70 in tougher conditions on the second day on the Majilis Course at the Emirates Golf Club.
Many pundits are also tipping Sweden's Henrik Stenson, the world number eight, South Africa's two-time US Open champion Retief Goosen and compatriot Ernie Els, both twice Masters runners-up, as lively challengers.