(Reuters) - Justin Rose birdied his first three holes on the way to a third-round four-under-par 66 on Saturday to take a four-stroke lead at the Fort Worth Invitational in Texas.
Rose, the world number five, is on 14-under and leads Brooks Koepka (67) and Emiliano Grillo (69), who are both 10-under par.
Koepka appeared poised to challenge for the lead but ran into trouble on the par-five 11th with a costly double bogey.
Louis Oosthuizen, Jon Rahm, Ryan Armour, Corey Conners and J. T. Poston are all tied for fourth at eight-under par.
"I'm happy with the way I played," Rose told CBS Sports.
"It was nice to get going and to build up that lead. No one seemed to do too much behind me today so I felt like it was in my hands to get as far ahead as I could."
The only blemish on his scorecard was a bogey on the par-three 16th on another sweltering day in Texas.
Rose managed to stay composed down the stretch but admitted the heat was a significant challenge.
"I struggled toward the end," he said.
"It was so hot out there I really felt I was battling the golf course and my concentration.
"It was tough to finish it off in that heat today but all in all, happy to be in the clubhouse. A good day's work."
2013 U.S. Open champion Rose will be paired on Sunday with Koepka, who won the U.S. Open last year.
"I don't think I can just rest on my laurels and shoot even par tomorrow. I've got to go forward I think," said Rose.
"I'm going to go out and just try to be doing what I've been doing that last few days and executing my shots and go from there."
(Reporting by Rory Carroll; Editing by Peter Rutherford)
