American Billy Horschel fired a nine-under par 63 to hold a one-stroke lead at the PGA Tour's rain disrupted True South Classic in Mississippi. Horschel made eagles at the fifth and the 18th in his bogey-free round to reach a 13-under 131 total at the halfway stage. Matt Bettencourt was one stroke back after a six-under 66, while first-round leader Jason Bohn must finish his second round on Saturday morning. He was placed at 12-under through the front nine. It was a tiring day for Horschel, who had to play 31 holes on Friday because heavy rains disrupted his first round the previous day. The 25-year-old battled through another rain delay on day two and faced blistering heat later on during his second round. Close to half the field will have to finish the second round on Saturday.