Ben James scorches into RBC Canadian Open lead after stunning 63

The 23-year-old American started with a eagle on the first hole and went from strength-to-strength as went to an overall 10-under at the TPC Toronto.

China's Haotong Li (67) and Americans Sam Burns (67) and Jackson Suber (65) were in a three-way tie a shot behind James, while first-round leader Brooks Koepka to be a further two shots back.

"I wasn't really thinking about results at all this week," said James. "Just worried about getting comfortable, making new friends and having fun, and just seeing where everything kind of falls. Just seeing where my game stacks up."

New Zealand's Ryan Fox, the reigning Canadian Open champion, had his second consecutive day with a 66. He was in a five-way tie for seventh after two rounds.

"My goal for the week was to be patient, and you've definitely got to be that (at TPC Toronto)," said Fox.

"You've just got to accept that you can hit a good shot that doesn't end up where you think it's going to and that that's OK, move on to the next one."