Shane Lowry birdied two of his last three holes to chisel out a level par 72 in the RBC Canadian Open, which bodes well for his US Open chances next week.

While he missed three putts inside five feet, leading to a double-bogey at the fourth and bogeys at the fifth and 11th, the former Open champion showed the kind of grit and patience he'll need at Los Angeles Country Club in the third Major of the season.

Lowry made five birdies at Oakdale Golf & Country Club, where thick rough and small, undulating greens make for a tough test in Toronto.

He's tied for 70th, a shot outside the cut mark, with Rory McIlroy tied 37th after a one-under 71 and qualifier David Carey joint 84th after a 73.

Despite his misses on the greens, the Clara man looks close to his very best from tee to green, and that will be important in the heart of Beverly Hills next week.

England's Aaron Rai, Americans Justin Lower and Chesson Handley share the lead with Canadian Corey Conners on five-under after 67s and lead by one shot from nine other players, including reigning US Open champion Matt Fitzpatrick.

McIlroy did not have his best stuff after an exhausting start to the week following the bombshell news that the PGA TOUR and the DP World Tour are merging with the Public Investment Fund of Saudi Arabia to create a new entity.

"I got a good night's sleep last night," McIlroy said. "So it was nice to sort of recharge the batteries. I would say my energy levels on Tuesday and Wednesday were diminishing quite quickly.

"But I slept well last night and honestly felt -- it was an early start this morning. The alarm went at 4:15. But I felt good out there. I'll do a little bit of practice this afternoon. Then I'll get another good night's sleep tonight, and I'll be fine."

McIlroy admitted he's ready now to "focus on the birdies and bogeys instead of the stuff that's happened in the boardroom".

He will need that focus if he's to become the first player to win the event three times in a row.

"Course is good," he said. "It's penal. If you miss fairways, the rough is very, very thick. "I certainly hit a few loose shots and got myself out of position, and the golf course does start to get quite tricky from there.

"So need to do a better job of just putting my ball in play off the tee. Then from there, the golf course is still quite scoreable."

Qualifier Carey was one-under par after back-to-back birdies at the second and third, his 11th and 12th, but three-putted the fourth and dropped another shot at the sixth to shoot 73 in his second start in a regular PGA TOUR event.

"Yeah, the rough is really thick," said the Dubliner, who came through a marathon day on Sunday to win his place in the field in a four-for-three playoff.

"So between that and the greens being really undulating, you have to really place your ball and think about what you're doing.

"I think if you can get far enough down the holes, like if you drive it well, you can, you can get out of the rough onto the greens. But if you choose to lay back and then you miss, it's going to be very difficult."

He has no concrete plans for the rest of the summer, bar Monday qualifiers in the US and heading home to try and qualify for The Open at Royal Liverpool.

As for his experiences in the US, he believes he's learning quickly.

"That was my first PGA Tour event," he said of qualifying for the Valero Texas Open in April, where he shot rounds of 78 and 76 to miss the cut. "It was definitely a learning experience, not just on the course but everything that goes with it and then the scale of things over here.

"I played The Open last year, but it's different playing links golf closer to home. This has been a different experience.

"I just got off to some bad starts there (in Texas). But there was some good golf as well. So it was really just trying to keep working and keep kind of building on the good stuff. And then trying to learn my lessons about maybe how I prepared and maybe some of the stuff going into the week, and you know, keep trying to get a little bit better."

As for his summer schedule, he grinned: "Well, that's a tough one. It's very much week to week. There are some more qualifiers, and then the final qualifying for The Open in the first week of July. It'd be nice to qualify for The Open again, but it is very much week to week. It's kind of hard to say."

ENDS