Rory McIlroy of Northern Ireland stretches before playing a shot out of the rough on the seventh hole during a practice round ahead of the British Open. (Cathal Mcnaughton/Reuters)

Pay no attention to what Rory McIlroy shoots in the first round of the British Open on Thursday, because it hardly matters. McIlroy has opened so many tournaments in spectacular fashion this year — a 63 at the Memorial, a 63 in Dubai, a 64 last week at the Scottish Open — that it is almost expected.

When he plays well in the second round, that will be news.

“It’s just got into my head,” McIlroy said Tuesday.

How could it not? McIlroy’s cumulative first-round score in 13 stroke-play events this year is 44 under par. He has broken par 11 times, and his worst performance was a 3-over 74 at the Irish Open.

McIlroy’s cumulative score in his 13 second rounds: 9 over, with some scores that don’t resemble those from a player of his caliber. There also have been massive swings. His opening 63 at the Memorial was followed by an inexplicable 78 the very next day on the very same course. Last week at the Scottish Open, he countered his first-round 64 with a second-round 78, going from 7 under after day one to even for the tournament.

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What gives?

“I may be putting a bit too much pressure on myself going out on Fridays and trying to back up a score,” said McIlroy, a two-time major champion and former world No. 1 who has fallen to eighth in the rankings. “I have no problem shooting a low one on Thursday. There should be no reason I have any problem shooting a low one on Friday. . . .

“It’s something that I need to go out and pretend like it’s a Thursday again and go out and just — I don’t know.”

This tendency isn’t wholly new for McIlroy. At the 2010 British Open at St. Andrews, he opened with a 63 and followed it with a ghastly 80. He finished tied for third, his only top-20 finish in six British Open appearances.

“The Open Championship is a tournament that’s very important to me, and my record in it hasn’t been as good as I’d like,” McIlroy said. “I’d love to improve on that.”

Rose on a roll

When Justin Rose arrived late last month at Congressional Country Club for the Quicken Loans National, he hadn’t won for more than a year and might have been something of a dark horse here. Instead, Rose won at Congressional, and on Sunday he fired his fourth consecutive round in the 60s to take the Scottish Open for his second victory in as many starts.

“I couldn’t have hoped for any better than that, obviously,” Rose said.

His form would seem to make him a favorite here. But history wouldn’t. Before Phil Mickelson did it last year, no Scottish Open winner followed it up with a victory at the British.

“Now that it’s been done, and somebody has won the week before and followed it up with the Open Championship, I think it’s an advantage,” Mickelson said. “. . . He’s playing well. He’s going to be in contention. I’ve got to believe that.”

Fever pitch

Martin Kaymer, the U.S. Open champion from Germany, has become friends with members of the German national soccer team over the years, and he was in contact with several in the run-up to Sunday’s victory over Argentina in the World Cup final. The players sent Kaymer videos of themselves putting and even playing golf on a nearby course to pass the time in Brazil. Germany’s first World Cup match came the day after Kaymer’s Open victory at Pinehurst, and star Thomas Müller mentioned Kaymer as inspiration in a post-match interview.

“It was very nice to see that we are all trying to work it out that golf becomes more important and bigger in Germany,” Kaymer said. “It’s a good relationship because it’s very natural. It’s not fake. It’s not forced.”