Kevin Na has been in this position before at Colonial.
He's been the co-leader after Day 1 a couple times, shooting a 7-under 63 in 2007 and a 6-under in 2015. He's back in that position this year after firing an 8-under 62 in Thursday's first round of the Fort Worth Invitational, highlighted by draining a 92-foot chip on his final hole of the day (No. 9).
But Na isn't taking anything for granted.
"There is a lot of golf left," Na said. "Look, I'm very pleased with how I played today. Going to go enjoy my dinner. After that, tomorrow is a fresh day, another day. Forget about today and try to go low again."
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Na then added, looking at the media official who mentioned it being his third time leading after 18: "He never said I won, did he?"
Na smiled and said: "There you go."
For Na, it will be a strong field to hold off for the next three rounds.
Justin Rose, ranked fifth in the world and playing for the first time since 2010, opened with a 4-under 66. Rickie Fowler, in Fort Worth for the first time since 2014, shot a 3-under 67. He made four birdies in a five-hole stretch and is tied for 19th.
"It’s great to be back," said Fowler, ranked sixth in the world. "It wasn’t that I didn’t want to be here by any means. I love Colonial and love the tournament, and the people here take great care of us.
"Solid start to the week. Not my best, but nice to get out there, get back into tournament golf, and get off to a solid start."
North Texas native Jordan Spieth, the top-ranked player in the field (third in the world), shot a 1-under 69. Jon Rahm, ranked No. 4, fired a 2-under 68.
But it was Na who posted the score of the day. He had a bogey-free round and went 6-under from Nos. 16-2.
"I like stretches like that," Na said.
Charley Hoffman is alone in second after a 7-under 63. He credited going to a heavier Scotty Cameron putter this week as part of the reason for his early success.
"It's worked so far," Hoffman said, smiling. "I can’t promise anything in weeks to come, but so far so good."