WATCH: Justin Thomas' horror drive

Justin Thomas had a moment to forget on the sixth tee during the third round of the Tour Championship.

The American, who had shared the lead overnight at East Lake, was one under for his round after five holes and playing steadily as he approached the easiest hole on the course - the par-five sixth.

However, Thomas produced a shot which commentator Butch Harmon described as "probably the worst shot he has seen him play" as he dragged his drive horribly to the left.

The ball darted into the trees down the left-hand side of the fairway and ended right behind the trunk of a tree.

Thomas was forced to play left-handed with the back of his club as he chipped out onto the fairway and he put his third shot into the rough at the left of the green.

The PGA champion needed three shots to get down from there as he posted a double-bogey six as his playing partner Paul Casey recorded an eagle three after playing the hole perfectly.

Click play on the video above to watch Thomas' horror drive........