Power and Scheffler four behind Moore in Texas
Seamus Power and Scottie Scheffler were three shots behind a red-hot Brooks Koepka despite opening with five-under 66s in the CJ Cup Byron Nelson in Texas.
The West Waterford man matched the world number one and defending champion when he rolled in a 29-footer for a closing birdie three at TPC Craig Ranch outside Dallas.
But they were still trailing five-time Major winner Koepka, who continued his encouraging return to form after rejoining the Tour from LIV Golf when he made an eagle and six birdies in an impressive, bogey-free eight under 63.
Taylor Moore later shot a nine under 62 to head Koepka and Jesper Svensson by a shot as Michael Thorbjornsen, Keith Mitchell, Tyler Duncan, Argentina's Emiliano Grillo, Korea's Si Woo Kim, Japan’s Kensei Hirata and Germany's Stephan Jaeger shot 64s to share fourth on a low-scoring day at the redesigned course.
Koepka, who described his putting as "absolutely horrendous" during last week's US PGA Championship, switched putters this week and immediately saw some results.
“Finally, I felt good with the putter," said the Floridian, who birdied his second hole and eagled the third to get a 25-putt round off to a fast start alongside Scheffler and Kim.
"I felt good the last few days with it when I was working in my studio. Then, when I got here, it felt very comfortable."
Koepka, who won the CJ Cup at Nine Bridges in Korea in 2019, believes a win this week would be the confidence boost he needs.
"I think, when I won it the last time, I got back to No. 1 in the world," he said. "It would be a big confidence boost for sure because I feel like I've been playing well, the results just haven't been there, mainly because of the putter.
"But I feel like I'm knocking on the door, and I'm very, very close. I would love to have a chance come Sunday."
Scheffler also had a disappointing week on the greens at Aronimink, but he was pleased to birdie three of his last five holes to remain in touch, tied for 16th with Power.
“I felt like I was getting lapped out there for a little bit," Scheffler said. "So I was fortunate to make a couple of birdies late in the round and keep myself in the tournament.
"I feel like sometimes in these tests, once you start getting behind, you can kind of start falling pretty far behind, and it can be difficult to catch up. It was nice to kind of stay in it."
As for Power, he was ranked first for strokes gained putting as he made 111 feet of putts and birdied the second and third before following a lone bogey at the fourth with birdies at the sixth, 12th, 14th and 18th.
On the DP World Tour, South Africa's Zander Lombard carded an eight-under 63 to lead the Soudal Open by a shot from Dane Jacob Skov Olesen and compatriot Richard Sterne at Rinkven International in Antwerp.
It was also low scoring in the Danish Golf Challenge at Odense Eventyr, where Kinsale's John Murphy and Galway's Liam Nolan opened with bogey-free, six-under 66s to share second place with Sweden's Adam Wallin, a shot behind Spain's Juana Salama.
But it was a mixed bag for the other eight Irishmen in action.
Mark Power turned in a sensational six-under 30 but came home in 42 for a level par 72 that left him tied for 68th with John-Ross Galbraith.
James Sugrue, Max Kennedy and Ronan Mullarney shot 73s, as Conor Purcell shot a 74, while Gary Hurley and Dermot McElroy signed for 75s.
At the LET's Lalla Meryem Cup at Royal Golf Dar Es Salam in Morocco, Anna Foster shot a level par 73 to lead the Irish challenge.
She was joint 30th, five shots behind Australia's Kelsey Bennett, who shot 68 to head the field by two strokes.
Aine Donegan was 44th after a 74, Sara Byrne 61st after a 75, and Annabel Wilson 76th after her 76.
