He is in a good mood too, having already laughed off comments from Tiger Woods and smiled at a remark made by Phil Mickelson.
The Americans were in New York on Monday to attend a Nike event before appearing together on the Jimmy Fallon Show. Before Woods headed home to Florida, McIlroy acknowledged that the injured 14-time major winner could not resist having a dig at now four-time major winning McIlroy.
"We talked about a few things and Tiger's telling me like I'm not going to let you win a green jacket next year and that he's going to," said the world No.1. "I just responded to Tiger saying I am looking forward to the challenge but he's super competitive.
"I might not look it but I'm the opposite. I've got a very competitive spirit but it would only be on a golf course. Like I'll let someone win in a game of pool. I don't care about that.
"But golf is my thing to be competitive at and it's my thing to succeed in, so of course I'm really competitive. Even if it doesn't look it, on the inside I'm trying to beat those guys to death on the course."
One of his rivals on the course, Mickelson, was able to bring a little levity to the unalloyed competition - the American asking McIlroy if he could 'hit through' on the last hole during yesterday's pro-am.
Mickelson was walking up on to the 17th green of the Ridgewood Country Club and spotted the Northern Irishman on the tee of the nearby 18th. "Hey, Rory? Do you mind if we can hit through," shouted Mickelson, in reference to the 'darkness' scenario on the final hole of the PGA Championship.
McIlroy saw the funny side of the remark ahead of the serious start to the four-event FedEx Cup Play-off Series. The contest begins in earnest today, with McIlroy looking to maintain his winning form as he pursues the $10m winning pot in Atlanta in a month's time.
Scotland's Russell Knox, meanwhile, is making his debut in the Play-off Series and will tee up at 12.53pm UK time in the company of Americans Brian Stuard and Daniel Summerhays.