Sweden's Oscar Floren carded a 6-under 66 on Thursday to grab a 1-stroke lead after the opening round of the Irish Open.
Floren is making his 13th start of the season, and he hasn't finished better than tied for 25th this season. He is winless in his career on the European Tour.
Irishmen Shane Lowry and Michael Hoey share second place at minus-5 at Carton House Golf Club. They were joined there by Peter Uihlein, Joost Luiten and Jean-Baptiste Gonnet.
Jose Maria Olazabal, Paul Casey and Thomas Bjorn are among six players tied for seventh at 4-under 68.
Graeme McDowell and Padraig Harrington both posted 1-under 71s, while world No. 2 Rory McIlroy struggled to a 2-over 74 on Thursday.
"No aspects of my game are standing out or are strong. I feel a little lost at the moment," McIlroy admitted. "I've just got to play and keep trying to shoot good scores. If anything, playing in front of (the home fans) should be a little boost."
Floren played the back nine first in round one and he started with three pars in a row from the 10th. He got on the board with an eagle at the short par-4 13th.
After four more pars, Floren birdied the par-5 18th to make the turn at minus-3. He made it two in a row with a birdie at the first.
The Swede grabbed a share of the lead with a birdie on the par-5 fourth. Floren came back with a birdie at the sixth to move to minus-6. He parred the last three holes to lead by one after the first round.
"I played great today. It was nice to get off good start today. I hit a lot of fairways, a lot of greens, and eventually a few putts are going to drop," Floren said.
"Mentally, I've changed a bit and put in the work, doing the smart things every day. After March/April, I changed things and it's been paying off. I've been in form the last few weeks, I finished well in Germany, but I played well in St. Omer and Austria the first two rounds as well."
Lowry, who won this title as an amateur in 2009, also started on the back nine and stumbled to a bogey at the 10th. He poured in three consecutive birdies from the 13th to jump to minus-2.
The Irishman birdied the 18th, then parred the first three of the front nine. Lowry birdied the fourth and eighth, both par-5s, to get to 5-under.
"I always hang out with Graeme Storm and Oliver Fisher and when the tournament was announced I said they could stay with me. I'm trying to keep my routine as normal as possible this week," said Lowry. "It would seem like there should be more pressure on me this week, but I'm looking at it as an advantage. I play this course week-in, week-out and know it like the back of my hand."
Hoey wrapped birdies at the second and fourth around a bogey at the third. He went on to birdie the sixth and ninth to make the turn at minus-3.
The four-time European Tour winner parred the first five holes of his second nine. Hoey birdied the 15th and 18th to get within one of the lead.
Uihlein and Luiten both mixed seven birdies and two bogeys in a their rounds of 67. Gonnet had six birdies and a lone bogey in his round of 67
NOTES: Floren carded four top-10 finishes in 2011, but his next best finish on tour was a share of 25th, which he did on three occasions ... Defending champion Jamie Donaldson opened with a 3-under 69 and is tied for 13th.