Paul Waring saw his lead cut to a single shot after the third round of the Abu Dhabi HSBC Championship.
The Englishman started the day five clear but a one-over 73 left the door ajar for the chasing pack.
Waring's 18-under-par total is one clear of Niklas Norgaard, with Tommy Fleetwood, Shane Lowry, Thorbjørn Olesen and Sebastian Söderberg tied for third on 15 under.
Waring found a bunker with his opening tee shot and had to scramble par from eight feet at the first, but looked to have settled down as he birdied the par-five second and hit his tee shot to eight feet at the short fourth.
However, he ran his birdie attempt five feet past and missed the return, before missing birdie putts at the next nine holes.
Finding sand off the tee at the 14th proved costly as he failed to save par from 15 feet.
Waring had produced the shot of his life with a fairway wood to inside four feet at the last on Friday, but 24 hours later ended up in a greenside bunker and had to settle for a 15th par of the day.
Norgaard had four birdies against a single dropped shot in his 69 and admitted he is starting to feel like he belongs at big events following his first DP World Tour win at the Betfred British Masters hosted by Sir Nick Faldo.