Brooks Koepka's reaction to electric bogey-free 63 at CJ Cup Byron Nelson

Brooks Koepka claimed he fed off the good energy of his playing partners after lighting up the first round of the CJ Cup Byron Nelson. 

The 36-year-old has generally played well since returning to the PGA Tour from LIV Golf in January. 

But the five-time major champion has been dreadful on the greens, forcing the American to constantly tinker with his putter.

The flatstick was on fire on Thursday, though, as Koepka mixed six birdies and an eagle for a bogey-free eight-under 63 at TPC Craig Ranch. 

"Yeah, I would say so," Koepka said when asked if it was the best round of his year. 

He played alongside defending champion Scottie Scheffler (66) and South Korea's Si Woo Kim (64). 

"Everyone is just kind of feeding off each other, [it was] easy," said Koepka. 

"Everyone's having fun. Makes it enjoyable. I feel comfortable on the golf course as well."

Koepka has changed putters multiple times this season and revealed in his pre-tournament news conference that he had switched to a mid mallet.

He started on the back nine and holed a 17-foot birdie putt at the 11th. 

A 13-foot eagle putt dropped at the 12th and he tapped on for birdie again from three feet at the 14th. 

After turning in 35, Koepka put more circles on his card at the second, fourth, fifth and sixth.  

It represented his first bogey-free round on the PGA Tour since the 2023 Masters and was only one stroke shy of matching his career-best.

"Finally, I felt good with the putter," Koepka added.

"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. Rick [Elliot, 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. J

"Just happy with the way everything went today."

Koepka made his return to the PGA Tour in January after managing to get out of his LIV Golf contract early. 

He won this tournament in 2018, two years after losing in a playoff to Sergio Garcia. 

Koepka said a victory would feel different this week as he is trying to make his way back into the signature events. 

"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, unsurprisingly, was the pre-tournament favourite this week. 

Several big names have skipped the tournament to re-charge their batteries after the PGA Championship. 

The 29-year-old carded a bogey-free 66. 

"I felt like I was getting lapped out there for a little bit," said Scheffler.  

"So I was fortunate to make a couple 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

"Brooks played great, and Si Woo played really nice as well. 

"Hopefully more of that the next couple days."