Resurgent Rory McIlroy part of leaderboard logjam at BMW Championship

The Northern Irishman signed for a six under 64 around Bellerive Golf Course, enough to join US Open champions JJ Spaun, Gary Woodland, Wyndham Clark and upstart Chris Gotterup.

McIlroy holed a 15-foot birdie at the fourth and recovered from a poor drive to take advantage of the par-five eighth. He then ended a run of pars by rolling in from eight feet at the par-three 13th. The Masters champion converted from five feet at the 15th before closing with a birdie-birdie finish to get to six under.

"I felt like I'm at least back on the right path of what I'm doing with my game and with my swing," McIlroy told reporters.

"It's certainly a work in progress. Days like this are encouraging, obviously, but there's still a lot of work to be done. For the first round with what I'm trying to do, it went as well as it could have today.

"I went home and I worked on a few things and at least got myself back in a frame of mind where like I felt like I'm at least back on the right path of what I'm doing with my game and with my swing. It's certainly a work in progress. Days like this are encouraging, obviously. There's still a lot of work to be done."

Further down the leaderboard, Matt Fitzpatrick and Japan's Ryo Hisatune are tied on five under. Meanwhile, Scottie Scheffler followed his eight-stroke victory last week with a disastrous even-par 72, his highest opening round since the US Open in June.