McIlroy, just 21, stamped his class on The Open, equalling the lowest ever round at golf's Majors.
The youngster ripped the defenceless Old Course to shreds, carding seven birdies and an eagle. And as he purred down the final 10-hole stretch in eight under, McIlroy looked every bit a Major champion in the making.
He led South Africa's Louis Oosthuizen by two, not much with 54-holes remaining in golf's oldest Major, especially with Tiger Woods, a two-time St Andrews winner, looming on five under.
But Harrington and McDowell both believe McIlroy has the game, the form and composure well beyond his years to become Irish golf's third Major champion in as many years.
McDowell, whose stunning victory at last month's US Open helped inspire yesterday's performance by McIlroy, believes his fellow Ulsterman and close friend is tough enough to take the |pressure over the next three days.
“Rory McIlroy is one of the most talented players I have ever seen. It doesn't surprise me that he's top of the leaderboard right now,” insisted McDowell, who carded a first-round 71. “The way he's playing, I fully expect him to be contending on Sunday afternoon.”
Harrington added: “It's obvious that if Rory continues to play that way, he's going to win the tournament. By shooting nine-under par, Rory has put himself in a great position.”
And as for the man of the moment, McIlroy admitted he had momentarily eyed a Major record-breaking 62.
“Definitely, I let one get away at 17 but I’m leading The Open; this is my best-ever round at St Andrews and I just love this place,” he said.
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