McIlroy finished 2012 on the ultimate high, ranked number one in the world and with a second Major championship in the bag. He won the money titles on the PGA and European Tours and signed a massive sponsorship deal.
But the early part of 2013 has not gone according to plan. Rather than press ahead, the 23-year-old has inexplicably slipped back with inconsistent play, losing his number one ranking and failing to win a tournament.
He has struggled with his game and also his head, succumbing to the pressure of expectation. At last month's Honda Classic in Florida, an event he won last year after repelling a late charge from Tiger Woods, he quit during the second round.
He apologised and explained that he was suffering tooth pain but was heavily criticised nonetheless. He later admitted he got it wrong and should have played on. A valuable lesson was learned.
"I realised pretty quickly that it wasn't the right thing to do. No matter how bad I was playing, I should have stayed out there," McIlroy told a news conference.
"Everyone makes mistakes and I'm learning from them ... I regret what I did but it's over now and it won't happen again."
Most of the speculation about his drop in form has centered on his decision to change to Nike clubs as part of a lucrative deal he signed with the manufacturer in January.
By McIlroy insists his new equipment is not the problem as much as the mind games he is battling.
"Coming off the back of last year, five wins, and a second Major championship in two years, I just really wanted to try and continue that and continue where I left off in 2012, and it's been frustrating that I haven't been able to do that," he said.
"And it doesn't make a difference what deal or what clubs I play, that's irrelevant. It's about me on the golf course and the expectations and the pressure that I put myself under."
McIlroy has shown some signs of progress in the lead-up to the April 11-14 Masters but whether he can return to his best in time to win the year's first Major remains to be seen. If there is one course in the world that will test McIlroy's nerves as much as his swing, it is Augusta National.
The Masters is the only Major where McIlroy has yet to finish in the top 10. Two years ago, he led the Masters by four shots at the start of the final round before suffering a meltdown, shooting an 80 to tumble down the leaderboard and finish tied for 15th.
Last year, he was tied for third at the halfway stage but crashed out of contention with a third round 77.
But McIlroy has shown he can quickly recover from setbacks. Two months after his 2011 Masters collapse, he won the U.S. Open at Congressional with a record total of 16-under-par to claim his first Major.
Four months after last year's Masters flop, he won a second Major, the PGA Championship, by a record margin of eight shots.
He has retained an irreverent humor and laidback manner that has made him a hit with the galleries and the sporting public and he spends his spare time watching and cheering on other athletes and teams, including his beloved Manchester United and his girlfriend, Danish tennis professional Caroline Wozniacki.
He has even formed a close relationship with Woods, who text messaged McIlroy after replacing him as world number one, urging the Northern Irishman to "pull his finger out" in time for the Masters.
"I didn't think I could go into the Masters under the radar," McIlroy said. "But I can sort of go in a little bit underneath him (Woods) so in a way it's not a bad thing.
"I probably wear my heart on my sleeve a bit with my golf. If I have a bad round, it's sort of like the end of the world, but if I play a good one, I'm happy again. That's just the way it goes."