Rory McIlroy's bid to claim his third Canadian Open title began in impressive style, sitting in a tie for sixth place and four shots off the lead after Thursday's opening round.
But in the wake of the Ulsterman's bogey-free round of 4-under-par, McIlroy admitted he was feeling "groggy" as he started his round on the 10th tee at Hamilton Golf and Country Club. The 35-year-old told golf journalist Adam Schupak after his round that he had a little too much wine celebrating caddie Harry Diamond's birthday on Wednesday evening.
There were no signs that McIlroy was hungover in his performance. He navigated the tricky back nine in level par before going up a gear as he hit the turn. McIlroy birdied the 10th and followed it up with three birdies in a four-hole stretch from five to eight to close in on the leaders.
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England's David Skinns leads the way in Ontario after a sublime round of eight-under-par, one shot clear of Sean O'Hair and Sam Burns. European Ryder Cup star Robert MacIntyre is solo fourth at six-under, with the Scotsman continuing an impressive run of form.
"So I played the back nine blind," McIlroy admitted after his round. "I hadn't seen the back nine, only played the front nine in the pro-am so I was happy enough to get out of there in even par and not make a bogey. But once I got those nine holes out of the way, I knew there were some chances on the front side and played much better. Four birdies and no bogeys was a good day's work.
"I've played a lot of golf this year. I'm on another four-week stretch, but it's been good. I've started to play my way into form and I've played well the past few weeks and hopefully, I can keep that going."
World No.2 McIlroy is playing his first event since finishing tied 12th at the PGA Championship at Valhalla earlier this month. That week, he filed for divorce from his wife of seven years, Erica Stoll, with his court papers stating that their marriage was "irretrievably broken".
The four-time major champion spent his week off flying to Italy to attend a friend's wedding before turning his focus back to the golf course, with hopes of ending his 10-year major drought with the US Open and The Open Championship on the horizon at Pinehurst No. 2 and Royal Troon respectively.
MacIntyre took his time to find his feet after making his PGA Tour debut this season, but he has hit form and finished in a tie for eighth at Valhalla. The Oban-born lefty is between caddies and had his father, Dougie, was on the bag in Hamilton on Thursday.
"It's the first time [he caddied for me] since tour school in 2017 or 2018," MacIntyre said. "We did alright there. I'm in a transition between caddies and I'm working it all out and it was an emergency phone call on Saturday and he stepped up to the plate.
"He's a good golfer himself but at this level, he's a bit out of his depth. But I thought he did a great job; he kept it so simple. He gave me the numbers and the numbers are what they are."