Lee opened with a three-under-par 67 to trail runaway English leader Harry Hall by five shots at Colonial Country Club, with Davis one stroke further back after carding a 68.

Three back-nine birdies, including one at the last hole, vaulted Lee into a share of seventh.

Backing up from a tie for 18th at last week's PGA Championship in New York, Lee offset two birdies with two bogeys on the front nine.

The 24-year-old is among 15 players at three-under, including World No.1 Scottie Scheffler and defending champion Sam Burns, who beat Scheffler in a play-off last year.

Davis, flying high after securing a Masters berth with a top-four finish at the PGA Championship, enjoyed a bogey-free round and picked up shots on the 1st and the 12th holes.

Fellow Australians Lucas Herbert and Aaron Baddley both shot even-par 70s but Harrison Endycott needs to make up ground in round two to make the cut after opening with a 74 to be tied for 106th in the 120-man field.

American club pro Michael Block, dubbed the people's champion after a fairy tale showing in New York last week, is running dead last after a nightmare 11-over 81 start.

Hall, the PGA Tour rookie, changed up his routine this week by playing 36 holes of practice at Colonial – a Monday pro-am and then nine holes on Tuesday and Wednesday. That helps, along with his putter.

"Maybe that's the key, just to see a bit more of the course than I have done in the past," the 25-year-old said.

"Been waiting for a round like that with the putter because I know I can get hot, and consistently I'm really good. Yeah, that was nice to hole some putts out there today.

"I didn't do too much different. I kind of just made things a little bit more simple.

"This feels nice to be on the leaderboard."