Sung Kang shot a 9-under 63 to take a six-shot lead in a record-breaking second round at the Houston Open on Friday.
After shooting a 65 on Thursday, Kang was at 16-under 128 through two rounds, setting the 36-hole tournament record of 129 by a stroke, set previously by Blaine McCallister in 1993 and Curtis Strange in 1980.
The 29-year-old South Korean, who entered the week ranked No. 202 in the world, bested the tournament course record at the Golf Club of Houston by three strokes, topping Johnson Wagner's 132 in 2008. Strange and Wagner went on to win those respective tournaments, while McCallister settled for a third-place finish.
Kang's 9-under on Friday matched the 18-hole tournament course record and helped him take the largest 36-hole lead in tournament history, topping the previous record by two strokes.
Hudson Swafford and Russell Henley were at 10-under after both shooting 5-under 67.