Korda rebounded from an opening 72 with a dazzling 6-under 66 at Tiburon Golf Club on a sunny, windswept day in south Florida. The bogey-free round included a hole-out for eagle on the third hole. The World No. 1 headed to the range after Thursday’s round and came away with one simple swing thought.

Sometimes, one little swing thought can change everything—even for the best player in the world. World No. 1 Nelly Korda bumbled to an even-par 72 on Thursday at the CME Group Tour Championship, a round well below her standard.

Narin An is the surprise first-round leader at the richest-paying event on the LPGA Tour. The South Korean played bogey-free for a 64 in the CME Group Tour Championship.