Shane Lowry's sunny attitude paid off when he equalled his career low on the PGA Tour and opened with a superb 64 in the RBC Canadian Open.

As Graeme McDowell birdied his last two holes for five-under 65 that left him tied sixth in his quest for a top-10 finish and one of three spots in The Open, a relaxed Lowry was just one stroke behind leader Keegan Bradley.

Twenty-four hours after getting soaked in the pro-am, the Clara native (32) made seven birdies and a bogey on a rain-softened Hamilton Golf and Country Club to share second with South Korea's Sungjae Im, South Africa's Erik van Rooyen and Canadian Nick Taylor on six-under.

"I pretty much hit the ball where I wanted to today and holed a few putts, so it was nice," said Lowry, who was forced to buy an umbrella from a fan during the pro-am.

”There was a couple sitting in the crowd, and they had an umbrella each, so I gave the lady $100 for hers," he said with a grin after a 25-putt round.

”It actually wasn't even a great one. It started to leak after a while. But, yeah, I got very wet yesterday, and I didn't actually get to see the whole course, but still, it was okay."

Wednesday's clouds proved to have a silver lining for Lowry, whose lone bogey came when he drove into "a huge divot" at the seventh.

The Offaly man has finished third and eighth in his last two starts and puts that down to his attitude.

”I think it's mentally more than anything physically," he said when asked what's clicked recently. "I think I've enjoyed my golf a little bit more over the last little while.

”Obviously, it's easier to enjoy it when you're finishing third and eighth. Hopefully, I can keep it going."

McDowell is not yet exempt for The Open in his home town, but he insisted he's put that to the back of his mind after taking just 24 putts in a six-birdie round.

”There is no doubt I want to be there," McDowell said. "I've got four golf tournaments where I am going to be trying as hard as I can — here, the US Open, the Irish Open and the Scottish Open — and there are spots up for grabs in all four.

“If I play well enough I will get there and if I don't play well enough, I don't deserve to be there."

McDowell was pleased to play well ahead of Pebble Beach, where he will tee it up with Dustin Johnson and Phil Mickelson in the first two rounds of the US Open at next week.

Winner at Pebble Beach in 2010, the Portrush man will go off the 10th at 4:13pm Irish time with two of the men who failed to catch him in the final round nine years ago.

Lowry tees off at the same time as McDowell but from the first tee with England’s Tyrrell Hatton and Amerian Gary Woodland.

Rory McIlroy will be the first Irish player in action when he sets off in search of his fifth major from the 10th at 3:51 pm Irish time with Spain’s Jon Rahm and Australian Marc Leishman.

As for Tiger Woods, the winner by 15 shots at Pebble Beach in 2000, the Masters champion will begin his quest for a 16th major and fourth US Open victory alongside Justin Rose and Jordan Spieth at 10:09pm next Thursday.

McIlroy (30) drove the ball well in Hamilton but was disappointed to post only a three-under 67 after putting a fourth wedge in his bag for next week's test where he knows precision wedge play will be key.

”I really feel like it was the worst I could have shot out there," said McIlroy, who hit some excellent wedges but struggled with his pace on the greens.

“I played well. Definitely an improvement on how I played last week at the Memorial."

On the extra wedge giving him more options between 120 and 150 yards at Pebble Beach, he said: "If I drive it well and give myself those shots, you really need to take advantage of those, especially at a US Open, where birdies are few and far between."

Seamus Power found just five fairways in a level par 70 while Pádraig Harrington was tied with an out-of-sorts Dustin Johnson, who had three three-putts, after a 71.

Meanwhile, Paul McGinley has persuaded two-time major winner Martin Kaymer to commit to next month's Dubai Duty Free Irish Open at Lahinch.

"I know how meticulous and thorough he is with his preparations, so it will truly be an amazing atmosphere on the West Coast, and I am looking forward to the challenge it poses," the former world number one said.

Paul Dunne and Gavin Moynihan will also be in Co Clare from July 4-7, but they first want to successfully defend their GolfSixes title at Oitavos Dunes this week.

 "It's a week we're looking forward to, the format sets up quite well for myself and Gavin, and hopefully we can do what we did last year but you just never know over six holes," Dunne said.

They face England Women, Sweden and Thailand in Group B with the winners and runners-up from each group making tomorrow's knockout stages.

“It's very different to last year, last year there were a lot of drivers and you could just be very aggressive off the tee,” Moynihan said.

“This year there's a lot of three irons or three woods and you just position it, really. You're not going to have long shots in for your second shots so you just have to be in the fairway and give yourself a look on each hole.

“I think it sets up well for us because hopefully it will be windy each day as well. We're looking forward to the week.

"I've been looking forward to this for the last few weeks. It's always great playing team golf, even going back to the amateur days, playing home internationals and Walker Cup, they're just a great week.

“Obviously the golf is the main event but you just have so much fun. Just enjoy it and then when you get on the golf course it's just normal business."

At the Swiss Challenge in Lucerne, Tullamore's Stuart Grehan and Cormac Sharvin shot level par 71s to share 70th place, eight shots behind Korea's Minkyu  Kim and Czech Daniel Suchan.

Ulsterman Daniel Peacock and Tramore's Robin Dawson were tied 85th after 72s as Derry's Ruaidhri McGee shot 74 and former Shamrock Rovers winger Stephen Grant a 77