Graeme McDowell was left cold by closing quadruple bogey eight but vowed to fight on despite his late body blow in the HNA Open de France.
As Paul Dunne fought his way into the top-10, firing a 67 that left him just five shots off the lead, McDowell's battling round was undone by two visits to the water at Le Golf National's treacherous closing hole.
"Never great making a [snowman] at the last!!!" McDowell tweeted after a 77 left him tied for 41st with Shane Lowry, nine shots behind young Swede Marcus Kinhult on three-over par.
"Play good and you are rewarded. Start missing fairways and you will be found out. Low weekend required."
It was a sad end for McDowell (38) who fought tooth and nail all day but was in trouble the moment he found water twice at the par-five third and made a double-bogey seven.
The two-time Open de France winner birdied the ninth to turn in one over, then recovered from another double bogey at the 13th with a birdie at the next.
He was still tied for 10th, one under for the tournament, facing a 190-yard approach over water at the 471-yard last.
But his hybrid from the semi-rough got a flyer and bounded through the green into the water before he compounded the error by duffing his fourth from the drop zone into the lake in front of him.
Swede Kinhult (21) impressively took advantage of easier morning conditions, picking up and eagle and six birdies in a six-under 65 to lead by two shots on six-under-par from England's Chris Wood, who shot a 68.
Spain's Jon Rahm is just three behind alongside first-round leader Bradley Dredge after a 69 with world number Justin Thomas lurking ominously a shot further back with Matt Fitzpatrick, Gregory Havret and American compatriot Julian Suri after a second successive 70.
Dunne birdied four of his first seven holes before cancelling out a bogey at his 16th hole with a closing birdie four.
"I think I hit my first eleven fairways in a row today and I was putting myself in a lot of positions to be attacking flags," said Dunne, whose 67 left him tied for ninth on one-under as Lowry struggled to a 75.
"If you are in the fairway the course isn't that difficult but the fairways are firm with lots of humps and bumps on them and hard to find. A score is out there, but you have to drive the ball well."
“It feels really good. I got off to a great start and played well from there. I guess the wind picked up a little bit on the back nine, the last four or five holes or so, but yeah, happy overall.
“I think it gets firmer throughout the day as well. So just hitting the fairways is a lot more tough. And on the back nine especially, it's a cross wind on every tee shot. So it's very important to get the right shape to be able to hit fairways.
“I haven't thought about it yet, but Saturday is going to be a big day, and hopefully on Sunday as well. It's a position I have never been in before, so we'll see.”
“You're going to have to grind over the week. I think I heard Matt Fitzpatrick say this morning there's not any hole where you feel like you get a stretch of where you can relax, but feel like there's a few chances.
“Every shot you have to be on it. It's brilliant, though. It's a great test. I've always loved the golf course, but never really been able to produce a score. So it's nice to put a score in today, three-under is pretty good out there.
“It's been pretty hard for a while now, but just got to keep going, just never give up really. Just keep working and eventually you'll see a glimmer of light.”
“The course was probably three shots easier than yesterday I would say. Played early in the morning when the greens were perfect, so shot one shot better. Actually played a lot worse and I was able to scramble a couple of holes. Probably about as low of round as I could have done today.
“Two of my poorest shots of the two days so far, ten and 15. Misjudged the wind both days, and today it was your poor decision. A little miss communication between me and Adam as well but that's what happens out here.
“I'm not the only one hitting balls in the water and I'm not the only one having bad luck on a couple of holes. It all balances out at the end. I also made a great putt on 11 starting out the day. That eagle on three at the beginning of the day, you can always look at some good breaks to balance it out.”
“It was one of the better rounds I've had in a while. I could have shoot a one under on the front easy, could have shot a three or four under. I had total control of my ball, drove it beautifully, hit some really, really quality iron shots. The greens are a little bumpy in the afternoon, so that made it difficult to make some putts, but I stayed patient and was able to make a couple there.”
“Just had one mistake on 17, I didn't hit a bad shot. I just kind of had a freaky little wind switch there and the ball went 20 yards farther than we thought it was going to. So it's unfortunate to finish how we did, but we really played well today.
“It's just a hard golf course - that in itself is the challenge - just playing this golf course. It's very narrow. You have to hit the fairways to have birdie chances into the greens. And I hit a couple of tee shots today that were literally a yard and a half off the fairway and I had a tough lie in the rough and you were just trying to make par from there.”
Hoey makes a move
At the Made in Denmark Challenge, Michael Hoey fired a five-under 66 to lie tied for 10th on five-under, seven shots behind Dane Mark Flindt Haastrup, who shot a 67 to lead by three shots from England's Marcus Armitage on 11-under.
Ballymena's Dermot McElroy shot a 74 to slip back to tied 21st on three-under with Jonathan Caldwell making the one-over cut on the mark after a 74.
Casey tenth as Young wins at Cumberwell Park
Brian Casey tied for tenth as Mark Young carded rounds of 65, 65, and 67 to win the Cumberwell Park Championship for his second win on the HotelPlanner.com PGA EuroPro Tour in as many weeks.
Young beat Brendan McCarroll, who is seventh in the Order of Merit, in last week's Jessie May World Snooker Championship at Clevedon.
As for Casey, now ranked 15th, the Headfort player closed with a six-under 65 to finish eight strokes behind the winner on eight under par.
Stuart Grehan was frustrated to bogey his last three holes for a 73 that left him tied for 19th on six-under.
The Tullamore man is 10th in the Order of Merit race for five Challenge Tour card.