Strong start for Campbell
Former US Open champion Michael Campbell was up into a tie for second after five holes of the Portugal Masters final round.
The 43-year-old New Zealander holed from five feet at the first and played a brilliant chip to two feet on the long fifth to reach 11 under par.
Austrian Bernd Wiesberger, seeking his third title of the season, resumed with four pars to remain 13 under, but England's Ross Fisher three-putted the fourth and slipped back alongside Campbell.
Fisher's compatriot Mark Foster was alone in fourth at 10 under and Ireland's Shane Lowry one further back.
In the testing wind, Wiesberger and Fisher both birdied the long fifth but the Vienna golfer failed to get up and down from sand at the difficult seventh.
They were 13 under and 12 under respectively - as they were at the start -
while Campbell made up for a bogey on the seventh with his third birdie of the day on the next and was still in touch two behind.
Lowry, whose win at his home Irish Open three years ago came as an amateur, caught Wiesberger with a spectacular start to the back nine.
After holing from seven feet at the 10th, his seven-iron approach to the next landed a foot short of the hole and hopped in for an eagle two.
He was level with the player who pushed him into second place at the Lyoness Open in Austria in July, while Fisher was one back and Campbell two behind.
It was a different story for Wiesberger on the 11th. He pulled his drive into the lake and bogeyed to leave Lowry alone in front, but the picture changed again when Fisher birdied the 12th and 13th.
He was ahead at 14 under, with Wiesberger also making four at the long 12th to be back alongside Lowry one behind.
Campbell, however, fell four adrift when he bogeyed the 13th and 14th.
Fisher made it three birdies in a row after an amazing drive on the downwind 424-yard 14th reached the front of the green, but Lowry then birdied the 15th and 17th and Fisher's bogey at the 16th left him one behind the Irishman again.