Jeff Hart and James Driscoll are tied for third place, six shots off the lead at 6-under-par.
Buha held a two-stroke lead when he reached the par-4 12th hole at the TPC at Wakefield Plantation. He hit a wild tee shot that 'was right of right in the high weeds somewhere.'
When he could not find the tee ball, Buha took the lonely walk back to the tee to hit his third and placed that drive into a fairway bunker. When Buha finally had a five-foot bogey save, the putt horseshoed around the cup and he left the hole with a double-bogey five.
'I was frustrated with myself a little bit,' said Buha. 'From there on in I knuckled down and hit the shots I needed to hit even though my swing wasn't there.'
Buha wedged his approach to three feet at the par-5 13th to set up birdie and after a par at 14, went on a birdie tear. He closed his round with four consecutive birdies to put distance between himself and Zorkic.
'I made all the putts from inside 10 feet today,' said Buha, who hit only 11 greens in regulation but took 24 putts Saturday. 'When you do that, you're going to play well. I finished off awesome.
'It was a wacky day. I hit it really, really ugly at times,' said Buha, a 27-year-old Duke graduate. 'My short game was awesome. It turned a round that could have been 2-over to 5-under - it was that good.'
Zorkic, who was born in Yugoslavia but raised in Australia, also had a late birdie flurry. He birdied 15 and 16 but missed a short birdie putt at 17 and took it out on the par-5 closing hole.
Zorkic ripped a 370-yard drive at the final hole and hit a 5-iron on to the green but tapped in for birdie after missing a long eagle putt he called 'an $8 cab ride.'
'I was a little pumped after missing that putt,' said Zorkic, referring to the birdie try at 17.
Full-field scores from the Buy.Com SAS Carolina Classic