After Scottie Scheffler's latest win at the Memorial Tournament, much of the talk coming into this week's RBC Canadian Open was how Rory McIlroy would respond in his first start since the PGA Championship.

McIlroy turned in 5-over 40 and then started his back nine in bogey-double-par-bogey. In danger of shooting in the 80s, he played his final four holes in 1 under. The 78 was McIlroy’s worst score since shooting the same number in the first round of last year’s Open Championship.

They went low on Thursday to open the 2025 RBC Canadian Open. There were were two 61s, a 62 and a 63 posted on the leaderboard north of the border after the first 18 holes. Nearly 100 golfers were under par late in the day Thursday.