It will clearly take more than blustering wind and hammering rain to stop Jordan Spieth at Royal Birkdale after he opened up a two-shot lead, posting a one under-par 69, in the second round of the British Open on Friday.
Spieth's two previous major victories came in 2015 at the Masters and the US Open. "I thought it was going to be like that for a lot of the round and I thought even par was an eight-under round when I was sitting on the couch".
"I played pretty solid today", said Koepka, who has barely played any golf since his US Open win.
Spieth spent Friday morning watching television coverage of the tournament, the wind blowing shots all over the course.
"I'm not a fan of tournaments that the outcome is predicted so much by the weather; it's not my sort of golf, " McIlroy said.
"I got off to a good start, which I think is really important today", McIlroy said.
The 44 year-old, whose only pro win was on the Challenge Tour in 2001, was tied for sixth after round one, two shots off the lead on a three-under 67, having finishing his opening 18 holes with three successive birdies.
Then, it turned out, a missing piece to the puzzle of winning the Claret Jug came on the practice ground ahead of his first round.
"That was one of my top five rounds at a major", the 23-year-old told reporters. "At that point I mumbled and said "Whatever" but it definitely helped".
And with the forecast predicting deteriorating conditions for Friday's second round, Spieth knows how valuable his great start could turn out to be.
Spieth acknowledged that he needs better driving but is clearly looking forward to the final two rounds, even if he is already feeling some butterflies. "It's trying to go up against Royal Birkdale and put on the best show you can against the golf course".
Ian Poulter got big cheers from the home crowd as he made his way around. In the past was his last time leading a major, when he let a five-shot lead get away from him on the back nine a year ago at Augusta National. But McIlroy made a double bogey on the 10th hole and was at 1 under.
"I was very proud of myself that I hung in there and tried to stay as positive as I possibly could", he said. He did just that, two-putting from off the back of the green to earn a standing ovation from many in the grandstands either side of the 18th green.
At the Travelers Championship last month he used three different putters on separate days, but he needed no such tinkering on the greens of the Southport links as he gave himself good chances at four of his first half-dozen holes and converted three. In April, he had Sunday problems on that hole again when he was in contention.