Brooke Henderson is trying to leave everyone else behind – and not get too far ahead of herself.

The 17-year-old Canadian took the outright lead in an LPGA Tour event for the third time this year, making birdies in three of her last four holes Friday for a five-under 67 and a one-shot advantage in the Cambia Portland Classic.

“I think if I can just stay patient and play my own game and not focus on outside factors, I think good things will happen,” Henderson said.

Playing in cool, breezy and sometimes wet conditions, Henderson finished with an eight-foot birdie putt on the par-four ninth to reach 11-under 133 at Columbia Edgewater.

She made her only bogey of the tournament at 11, but rebounded with birdies at 12, 14 and 3 before the late burst.

Henderson is attempting to become the third player to win an LPGA tournament before turning 18, joining Lydia Ko and Lexi Thompson.

“That would be really good, but I’m still a long way from that, and I realise that,” Henderson said. “I have to go low and shoot some good numbers.”

Minjee Lee is the best-placed Australian at four under to put her in a tie for 30th.