Britain's Luke Donald endured an up-and-down third round at the Byron Nelson Championship but emerged with a one-shot lead going into the final round of the $6.3 million event.
Donald shot a 67 for a three-round total of 200, 10-under-par, one better than Dallas native Scott Verplank who shot a 66.
American Michael Allen is a shot further back in third place after an eight under par 64, with Briton Ian Poulter is fourth on 204 for the three rounds.
Vijay Singh and Phil Mickelson are among five players tied for fifth on 205.
"I know I'm the kind of person that's good enough to win this tournament tomorrow," Englishman Donald said.
"I felt like I was very patient today. With the weather conditions being so mild.
"I knew there were some scoring opportunities out there and I made some nice birdies on the back nine," he added.
Donald shot an even par 35 on the front nine and at one point was three shots behind Verplank, who grew up 20 miles from the course and once served as a volunteer sign carrier at the tournament.
But the back nine of the Tournament Players Course at the Four Seasons Resort was a different story - Verplank shooting even par 35 while Donald went three-under.
"Everybody knows how I feel about this tournament and Mr. Nelson," Verplank said. "It would be the highlight of my career to win here."
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