Two dropped shots in his final three holes took the gloss off Ryder Cup captain Darren Clarke's opening round at the Houston Open on Thursday.
Clarke, who will play in his 13th Masters next week, had been progressing nicely at three under but had bogeys at 16 and 18 to card a one-under-par 71.
It placed the 46-year-old Northern Irishman eight shots behind clubhouse leader Scott Piercy of the USA.
Clarke qualifies for Augusta because of his 2011 Open triumph.
He has missed the cut on each of his last four appearances at the Houston tournament.