Rory McIlroy charged into the lead in the final round of the Alfred Dunhill Links Championship with a brilliant front nine of 30 at soggy St Andrews.
Northern Ireland's McIlroy started the day five shots behind compatriot Michael Hoey, but carded four birdies and an eagle to move to 19 under par.
The US Open Champion birdied the second and then holed his second shot to the par four third for an eagle two, his approach pitching past the flag but spinning back into the hole.
Further birdies at the sixth, seventh and ninth took McIlroy out in 30 and into a one shot lead over Hoey, another countryman Graeme McDowell - the man he succeeded as US Open Champion - and Scotland's George Murray.
McDowell was three under for his round after seven holes while Murray almost matched McIlroy's outward nine, five birdies taking him out in 31.
Overnight leader Hoey had carded two birdies and two bogeys in eight holes to remain 18 under.
Hoey briefly drew level with McIlroy again thanks to a birdie on the ninth, but McIlroy then hit a superb tee shot to within two feet of the hole on the 11th to move ahead at 20 under.
McDowell birdied the 12th from five feet to join Hoey in second on 19 under, meaning Northern Irish players were on course for an unprecedented 1-2-3.
Surprisingly none of the top three were able to make birdie on the par five 14th - Hoey three-putting from the front edge after hitting a driver off the fairway for his approach - but Hoey did birdie the 15th from six feet to join McIlroy in the lead at 20 under.
McDowell remained one behind with Scottish pair George Murray and Marc Warren another stroke back on 18 under.
Hoey then reclaimed the lead with his second birdie in a row, a superb approach to the 16th leaving him just two feet away from the hole.
McIlroy's long-range birdie attempt on the 17th narrowly slipped by, leaving the US Open Champion one behind with one to play.