Padraig Harrington finished on 10 over par after a final round 73 left him 15 strokes off the current lead pace in the U.S. PGA Championship.
The Dubliner recorded bogies on the fourth, seventh and 10th to leave himself in an early 34th position overall.
Meanwhile Tiger Woods is set for his worst major finish as a professional after carding a three-over-par 73.
The world number one, struggling for accuracy off the tee all week, lost any chance of mounting a last-day charge with two bogeys in his first three holes, and then dropped three more shots between the 10th and 15th holes.
Although he finished strongly with birdies on 16 and at the last, lifting his meagre birdie haul for the week to six, he finished at 12-over par in an early tie for 42nd place in a field of 69.
"It was frustrating out there but I'm so happy now that I'm done," said Woods, who hit just eight of 14 fairways in the final round. "If I wasn't making a 10-footer for par, I was making a bogey somewhere.
"It's tough and it's hard to get the ball close. When you're not as precise as you need to be, it's going to be tough.
"This golf course is just a brutal test. It's the hardest, fair golf course I've ever played."
Woods had completed his first season without a major victory since 1998.
Although he has made every cut in the 28 majors he has played as a pro, his worst finish has twice been a tie for 29th, in the U.S. PGA Championship at Winged Foot in 1997 and again at Atlanta Athletic Club in 2001.Woods aside, the 85th PGA Championship is poised for an unpredictable finish with 17 players grouped within seven of the overnight lead going into the last day at Oak Hill Country Club's East Course, where trouble lurks on virtually every hole.
The fairways on the par-70 layout are tight, with an average width of just 23 yards, and the thick rough is amongst the toughest ever seen at a major championship.
Overnight leaders Chad Campbell and Shaun Micheel had mixed starts to their rounds, with Campbell dropping two shots early on and Micheel birdeying twice and bogeying once to leave himself on five under through five holes.
Campbell and Micheel are both hunting their first PGA Tour wins, and will be fully aware that former major winners Mike Weir, Ernie Els and Vijay Singh are all within striking distance.
U.S. Masters champion Weir, bidding to become the first player since Jack Nicklaus (in 1975) to clinch the first and last majors of the season, is three off the lead at one under, Els is a further two strokes back and 1998 winner Singh was tied for ninth at two over par.
All three players carded third-round 70s.