Frenchman Gregory Bourdy fired a five-under-par 67 to take the outright lead after the Irish Open second round on Friday while triple major champion Padraig Harrington boosted his chances of claiming a home victory.
Three-times European Tour winner Bourdy has yet to finish in the top 10 this season, but he did his title hopes a power of good by recording a 12-under total of 132.
He is one stroke ahead of Briton Mark Foster (67), with Harrington (67) sharing third place on 134 alongside Italian Lorenzo Gagli (66) and Briton Paul Waring (65).
Harrington is the only home winner of the Irish Open in the last 30 years, but he is without a trophy since lifting the Johor Open title in Indonesia in 2010.
This week's tournament is a sellout and the Irishman said he was blown away by the size of the crowds at Royal Portrush in County Antrim.
"It sounded like a British Open coming down the 18th," he told reporters.
"The crowds were clapping us from 150 yards short of the green, as they were all day.
"Particularly on the last six holes, when the rain went away and the umbrellas went down, there was rapturous applause and cheering as we approached the green.
"It's unique and great to see. I think all of the players, especially the players down the rankings, aren't used to this so they really appreciate it," added 2007 Irish Open winner Harrington.
Having compiled what he considered the finest round of his career on the opening day, Bourdy joked that his second-round effort was "maybe the second best round of my career".
The Frenchman, who was joint leader overnight with Indian Jeev Milkha Singh, picked up six birdies and an eagle but also dropped shots at the fourth, 11th and 14th.
World number two Rory McIlroy (69) and 11th-ranked Graeme McDowell (68) were seven strokes off the pace on 139. British Open champion Darren Clarke (69) was a further shot adrift on 140.
Among the players to miss the cut were U.S. PGA winner Keegan Bradley, Italian Matteo Manassero, eight-times European number one Colin Montgomerie and European Ryder Cup captain Jose Maria Olazabal.