FORT WORTH -- On a go-low Sunday at Colonial Country Club, Kevin Na tied the course record and five others shot at least six under.But Justin Rose wouldn't budge.By following the aggressive strategy that produced his four-stroke lead to start the day, he kept drama to a minimum and stayed out of reach.Rose fired a six-under 64 to win the Fort Worth Invitational by three strokes over Brooks Koepka, who shot 63, and Argentina's Emiliano Grillo, who shot 64.Not even Kevin Na's remarkable 61, which tied the course record, could distract Rose from his intended target.