Connors played like it on Thursday, shooting five-under to share the first-round lead at the Canadian Open at Oakdale Golf & Country Club in Toronto. It's a packed leaderboard, with Englishman Aaron Rai and American duo Justin Lower and Chesson Hadley also carding 67s.

One shot off the pace is a group of eight that includes Matt Fitzpatrick, the No.8 ranked player in the world who will defend his U.S. Open title next week.

Aaron Baddeley is the best-placed Australian at joint 37th, one-under the card, with Harrison Endycott (72) even, Geoff Ogilvy (74) two-over and Cameron Percy (75) a further shot back.

Conners will no doubt receive strong support as he attempts to become the first Canadian to win the event since 1954.

Countrymen Mackenzie Hughes and Taylor Pendrith also enjoyed strong opening rounds. They are at three-under-par in a large chasing pack that also includes former World No.1 Justin Rose of England.

"It's great," Hughes said of the strong showing by the Canadian trio.

"It's one day of golf. You can't win it on Thursday, but you can lose it ... looking forward to tomorrow morning."

Northern Ireland's Rory McIlroy is the top-ranked player in this week's field at No.3. He's also the two-time defending champion (the event was not held in 2019-20 due to the COVID-19 pandemic).

After two hectic days since the announced merger of the PGA Tour, DP World Tour and the Public Investment Fund's golf properties, McIlroy had an up-and-down round that included five birdies and four bogeys. At the end of the day, he was four shots off the lead while playing in a group with Rose.

"Rosie and I said, 'All right, no chatting until lunch so that we can actually concentrate on what we're doing out there'," McIlroy said.

"We started to get in a conversation walking down the 1st (hole) and we're like, 'No, let's stop this. Let's just focus on our golf and we'll say what we want to say when we get inside.'

"So, it was nice to play a round of golf and focus on something else for those five hours we were out there."