Graeme McDowell improved by 10 shots on his dismal third round at the Wales Open but his closing 71 still left him well down the field at Celtic Manor.
The holder finished on three over which left him 12 shots behind winner Alexander Noren, who was two clear of Gregory Bourdy and Anders Hansen.
Darren Clarke slumped to his second successive 80 as he finished on 18 over - second last of the finishers.
Michael Hoey shot a closing 77 to finish on 10 over.
McDowell went into the weekend with high hopes of defending his Welsh title but a shocking third round which included three bogeys and a quadruple bogey plummeted the US Open champion down the leaderboard.
His round on Sunday had its ups and down with four birdies cancelled out by the same amount of bogeys as he ended up in a share of 30th place.
Missing a short par putt on the last may not have done his battered confidence any good in his last competitive round before he puts his US Open title on the line next week.
Clarke is not going to forget Celtic Manor's 14th hole for a while.
After a quadruple-bogey eight there in the third round of the Saab Wales Open, he took a 10 on the hole on Sunday.
After driving into the lake the Ulsterman went to the drop zone and hit two three-woods back into the water.
"And I hit them all well," he said after a second successive 80 made him 18 over par for the tournament.
"Let's just say this course does not really fit my eye.
"It never has done - and I putted unbelievably poorly as well."
Never before in a European Tour career going back to his debut as an amateur in 1990 has Clarke failed to break 80 in two successive rounds.
Hoey's closing 77 included three double bogeys, three bogeys and third birdies.
Damien McGrane was the best Irish finisher in a share of 28th after a closing 73.