Graeme McDowell has admitted that a 'Pebble Beach hangover' contributed to a mixed performance at St Andrews and a final day showing which he described as "amateur."
The U.S. Open championed ended the tournament with a final round 70 for three under par.
"I'm not quite myself at the minute in terms of getting my head screwed back on but after these last two weeks it could have been a lot worse," the Portrush man said.
"I played beautifully today, the best I've played all week but I finished like an absolute amateur - three-putting 16 and four-putting 17.
"I didn't quite get the job finished and it has been a frustrating week.
"Tee to green I controlled my ball pretty but I putted diabolically, which is unlike me on this type of green."
The 30-year-old continued: "I didn't clean up this week the way I cleaned up around Pebble Beach.
"I gave myself plenty of chances to compete but from four to 10 feet I putted badly.
"It would have been nice to have rescued a few shots. I could have gone really crazy but missed a ton of chances today - maybe I used up all my putts at Pebble."
As the final day of golf played at St Andrews Northern Ireland's Rory McIlroy is sitting in fifth place, seven under par.
Dungannon man Darren Clarke has ended with a 71 for level par.
South Africa's Louis Oosthuizen leads the way from Paul Casey by four shots.
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