Séamus Power has made a strong start to the CJ Cup Byron Nelson in Dallas with an opening round of 66.The Waterford man had six birdies and one bogey in a five-under-par round that left him three strokes behind clubhouse leader Brooks Koepka in the PGA Tour event.Power had an outstanding day on the greens at TPC Craig Ranch, gaining almost three strokes on the field, although his most exceptional shot came at the third hole when hit his approach to six inches from the hole for a kick-in birdie.It is a return to form for Power, who has struggled for form of late, missing two of his last three cuts and finishing tied 60th two weeks ago at Myrtle Beach.Koepka’s superb eight-under-par round 63 came after returning to a Scotty Cameron putter after putting woes at the PGA Championship which saw him miss several putts after good approaches.“Finally, I felt good with the putter. I felt good the last few days with it when I was working in my studio,” he said. “Then when I got here, it felt very comfortable. Ricky [Elliott, his caddie] said the same thing from watching. Which also kind of helps build a little confidence, what you feel versus the reality of it. Just happy with the way everything went today.”Koepka was part of a low-scoring marquee group with Si Woo Kim, who shot 64 and world number one Scottie Scheffler who matched Power’s score of 66. Before the tournament, he was the shortest price since Tiger to win a PGA Tour event with the bookmakers, having won the tournament by eight strokes with a 31-under-par total last year.