(Photo credit: Raymond Carlin III-Imagn Images)

Brooks Koepka is part of a five-way tie atop the leaderboard after one round of the RBC Canadian Open on Thursday in Caledon, Ontario.

The five-time major winner shot a 6-under-par 64 at TPC Toronto at Osprey Valley's North course, as did Sahith Theegala, Eric Cole, Sam Burns and Argentina's Emiliano Grillo.

Koepka has been back on the PGA Tour since January after more than three years away with LIV Golf. He's placed in the top 20 in six events this year, but a win this weekend would be his first in a standard PGA Tour event since the 2021 WM Phoenix Open.

Koepka shot a 5-under 30 on the back nine with three sets of consecutive birdies, including Nos. 17-18, against one bogey. He was among the leaders in the field in putting, having made a 17 1/2-footer for birdie at the par-4 ninth hole and a 19-foot birdie at the par-3 14th.

A bevy of players were tied at 5-under 65 as the final few groups finished up Thursday afternoon. That included Ireland's Shane Lowry, low Canadian Adam Svensson and Tony Finau, who is aiming to turn around a disappointing season and qualify for next month's Open Championship.

The top three finishers in Canada not otherwise exempt will qualify for the Open at Royal Birkdale. Finau has yet to play in a major this year.

Other Canadians in the mix include Taylor Pendrith (4-under 66) and Nick Taylor (3-under 67). Taylor was the first Canadian since 1954 to win his national open when he sank a 72-foot eagle putt to win a playoff in 2023.

England's Tommy Fleetwood, who was on the wrong side of that playoff, opened Thursday with a 3-under 67, as did countryman Matt Fitzpatrick.

--Field Level Media