Adrian Otaegui birdied his last three holes and carded a 6-under-par 66 to take a 1-shot lead at the Qatar Masters.
Otaegui moved to 11-under overall after the second round and clear of four players tied for second at Doha Golf Club.
Overnight joint leaders Eddie Pepperell and Gregory Havret shot 69s to go to 10 under, and they were joined by South African Challenge Tour graduate Erik van Rooyen (66) and Scottish veteran Stephen Gallacher (66).
Jessica Korda shot a course-record 62 at the LPGA Thailand on Friday to lead by 4 strokes after the second round.
Playing her first tournament since having jaw surgery, the American fired eight birdies and finished with an eagle to move to 16 under par at the halfway point, a 36-hole record for the event.
Korda is the daughter of former tennis player Petr Korda. She leads over another American, Brittany Lincicome, who carded a 65 to go 12 under at the Siam Country Club Pattaya Old Course.
Minjee Lee of Australia is third and a shot behind Linicome. Lexi Thompson of the United States, the 2016 champion, is fourth and another shot behind Lee.
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