France's Mike Lorenzo-Vera overcame a lung infection to shoot the lowest-ever round at the DP World Tour Championship on Thursday, while Bernd Wiesberger stayed in pole position for the season-ending Race to Dubai title.
Lorenzo-Vera holed four straight birdies to finish the back nine at Jumeirah Golf Estates, carding a nine-under-par 63 in the opening round as he matched his lowest-ever score to par on the European Tour.
The 34-year-old made a flying start with an eagle on the par-five second and a birdie on the third and while he dropped a shot on the next, another gain on the seventh gave him a share of the lead before taking full control.
Having struggled with illness during a final-round 80 at last week's Nedbank Golf Challenge, Lorenzo-Vera was pleased to claim an early one-shot advantage at the European Tour's season-finale in Dubai.
"Honestly I'm not feeling well at all," he said. "I have no energy. I had a big lung infection in South Africa and a big treatment and really feel bad on top of that.
"I felt that if I really relaxed a lot, just swing it like 70% or maybe less, the ball was still flying pretty well. Try to be pretty clever and not too aggressive and then the putter got hot. So that worked."
World number two Rory McIlroy had five birdies and three lip outs on the front nine and finished with an eagle at the par-five 18th following an incredible second shot with a wood from the middle of the fairway that landed three feet from the hole.
Race to Dubai leader Wiesberger, who needs a win or a solo second in Dubai to guarantee that he wins the Harry Vardon Trophy, finished the day at two-under, a shot clear of fellow contender Matthew Fitzpatrick and three ahead of British Open champion Shane Lowry.
Spain's Jon Rahm, who is also among the five players who can be crowned the European Tour's Order of Merit winner this weekend, piled the pressure on Wiesberger with a bogey-free 66.
England's Tommy Fleetwood, who moved up to second in the Race to Dubai Rankings with victory at the Nedbank Golf Challenge last week, continued his brilliant run with a 67 to sit alongside compatriot Tom Lewis four shots off the lead.