TORONTO - Wyndham Clark held on to his one-stroke overnight lead at the Canadian Open on Friday as the American carded an even-par 70 during second-round play at St. Georges Golf and Country Club.

The Colorado native was seven-under 133 through 36 holes at Canada's national championship, an 8.7 million U.S. dollars PGA Tour event.

Defending champion Rory McIlroy carded a 68 in sunny but windy conditions to sit equal second with England's Matthew Fitzpatrick (70) and Americans Alex Smalley (67), Jim Knous (67) and Keith Mitchell (67).

World No. 1 Scottie Scheffler, the reigning Masters champion, improved to a 67 to sit three strokes back.

Clark, a 28-year-old journeyman who is in the hunt for his first PGA Tour win, jockeyed back-and-forth with Fitzpatrick for the top position on the leaderboard for much of the day. Fitzpatrick got to 10-under through 11 holes but stumbled down the stretch to card three straight bogeys from the 17th. Clark was equally erratic as his round included three birdies and three bogeys, all of which came over the last seven holes.

"Honestly, I played really good," said Clark. "It was tough out there. It was windy, there was some tough pin placements. These greens are very tough and you get into some tough spots where you have to be defensive even from 10, 15 feet. Overall, I played really good. I felt really confident with my game."

Ulsterman McIlroy overcame a slow start to finish strongly with two birdies over the final four holes to get close. "It was a good score today. I scrambled well when I needed to. I didn't really take advantage of how well I hit it off the tee. But overall, I felt it was, a couple under was a fair reflection of how the day went," said the four-time major winner whose round included four birdies and two bogeys.

Notable scores included 2019 British Open winner Shane Lowry (69) at four-under. PGA Championship winner Justin Thomas (69) was two-under, a stroke ahead of Englishmen Justin Rose (70) and Danny Willett (68). World No. 4 Cameron Smith battled back from an opening round 76 to post a five-under 65 and finish plus-one to make the cut.

Cao Yi, the lone Chinese mainland player in the field, shot his second consecutive round of two-over 72 to miss the cut by three strokes.