Fresh from achieving his career slam of winning all four majors, the Northern Ireland ace provided an anti-climactic opening at his banker Quail Hollow course in Charlotte, struggling to a three-over par 74 among the early wave on Thursday.
It already left the 36-year-old having to play catch-up as surprise American leader Ryan Gerard set a hot pace, recording a five-under 66 to hold the early clubhouse lead by a stroke. Â
Behind the 25-year-old came a quartet on four under - veteran European Ryder Cup captain Luke Donald, New Zealander Ryan Fox, American Alex Smalley and Germany's Stephan Jaeger.
While McIlroy already lies eight adrift, the early Australian contingent also didn't have a great morning, with former champ Jason Day ending up with a two-over 73, while Min Woo Lee shot 74 and Karl Vilips a poor 78.
McIlroy's play-off victory over Justin Rose at Augusta in April made him just the sixth man to complete the career grand slam and it was expected to free him up for a spectacular assault at the venue where he has enjoyed so much success and holds the course record.
But at the North Carolinan course where he won his first PGA Tour title in 2010 and has since claimed three more victories, including last year, the man of the moment could only hit three fairways in regulation and flirted with the water with pulled tee shots in an uncharacteristically sluggish display.
His playing partners in an early morning 'super group' Xander Schauffele and Scottie Scheffler, also made hard work of it as they started from the 10th tee, with the remarkable sight of all three suffering double bogeys on the 16th, where the two American luminaries both found the water.
World No.1 Scheffler, though, battled back to finish handily placed at two under while defending champ Schauffele was one over.
The 47-year-old Donald showed them the way with a splendid bogey-free 67 while there was delight too for Fox, son of former All Blacks' World Cup winner Grant Fox, who capitalised in grand fashion after securing his place in the field last Sunday by winning his first PGA Tour title at Myrtle Beach.
Gerard, who played collegiate golf for North Carolina, was left a mite frustrated after his lead could have been ever bigger if not for dropping shots at his last two holes after having recorded four straight birdies and an eagle in his first six holes after the turn.
With agencies
