Wyndham Clark held his Canadian Open lead after the second round, although Matt Fitzpatrick and Rory McIlroy continue to breathe down his neck.
Clark and Fitzpatrick both struggled to recreate their magic from day one and carded and even 70 each, but that was enough to preserve their positions on the leaderboard.
McIlroy continued to push behind them, though, producing a two-under 68 to close to within just one stroke of the lead, with Alex Smalley, Keith Mitchell and Jim Knous also in joint second spot.
The Northern Irishman won the tournament by seven shots in 2019, but the pandemic cancelled the last two years of the event, leaving him unable to defend the title until now.
England's Matt Wallace and Ireland's Shane Lowry are a further two shots back on four under headed into the weekend.
Last month, Fitzpatrick missed out on his first major title by two strokes in the US PGA Championship at Southern Hills.
"A couple times my body shut down and I hit a couple left shots," Clark said following his second round.
"I felt really good. I didn't feel terrible with my ball striking. I just, it was a little tougher, the wind was sporadic and if you missed some fairways it's hard to hit the greens.
"I have a great short game and I'm a good putter so if I miss greens I don't freak out too much. Going forward on the weekend I would like to hit some more greens.
"So I'm not too concerned. I think I'm going to hit it great tomorrow."