American Xander Schauffele took over at the top of the leaderboard as the second round of the WGC – Mexico Championship began at Chapultepec Golf Club.
South Africa's Louis Oosthuizen held a one shot advantage overnight, but could only turn in a level par 36 and Schauffele took advantage with birdies at the 14th and 15th to advance to eight under par.
That was one ahead of former Open Championship winner Oosthuizen, who failed to get up and down on the 13th but then birdied the long 15th to regain the shot.
Spain's Rafa Cabrera Bello, England's Chris Paisley and Race to Dubai leader Shubhankar Sharma were all tied for third on six under as the European Tour contingent continued to put in a strong showing.
India's Sharma, already a two-time winner this season, was level par through six holes, Paisley had parred the opening hole and Cabrera Bello joined them on six under with a birdie at the first.
