Jordan Spieth five shots off the pace in Texas
Jordan Spieth continued to struggle for top form as he finished five shots off the lead in the first round of the Dean & Deluca Invitational.
It could have been worse for the defending champion as he closed his round with back-to-back birdies to finish level par, after a double bogey on the 15th had been followed by another dropped shot on the 16th.
Spieth has missed the cut at his last two events but had hoped a return to form was on the cards in his home state of Texas.
The 23-year-old bogeyed the second and fourth but returned to level par by gaining shots on the fifth and seventh.
A 38-foot putt saved par on the ninth before a dropped shot on the 10th was followed by b irdies on the 11th and 13th to take him under par for the first time.
But he struggled on the par-four 15th, finding the bunker from his drive before his next shot ended up in a water hazard.
When he followed that up with a bogey on the next, the two-time major winner was seven shots off the pace, but an impressive end to his round will give him confidence for day two.
Northern Ireland's Graeme McDowell made a strong start to the tournament, with his four-under 66 leaving him a shot behind joint leaders Derek Fathauer, JT Poston and Kelly Kraft.
McDowell, who is without a top-10 finish on the PGA Tour this year, started on the back nine and birdied the 11th, 18th, fourth and seventh.
He goes into the second round in a tie for fourth with American Scott Brown and Spain's Jon Rahm.
Five-time major winner Phil Mickelson is one of six Americans lying a further shot adrift after he birdied the last three holes, while Masters champion Sergio Garcia is five shots back after an opening 69.
England's Paul Casey joins Garcia on one under after he double bogeyed the 17th.