Only in the Wentworth estate, where money actually grows on the trees and Bruce Forsyth probably has a herbaceous border that's made out of £50 notes in the garden of his elaborate mansion, could the purchase of a Ferrari be greeted with a nonchalant shrug.

"Yeah, it's nice," said Rory McIlroy as he casually reflected on his acquisition as if it was a freshly baked Forfar bridie. It was Pro-Am day on the eve of the BMW PGA Championship, a point and gawp smile-fest that sees a vast gathering of grinning celebrities, sporting personalities and more hangers on than a rock pool of barnacles take charge of the West course. In this golfing showroom, McIlroy is the classic marque who has hit top gear. There were one or two misfiring engines, mind you. Padraig Harrington was forced to withdraw from the pre-tournament batter about with a "frozen shoulder" while Stephen Gallacher also pulled out with a worrying bout of tendonitis in his wrist and, prior to getting an injection yesterday, rated his chances of teeing-up in today's opening round of the European Tour's flagship event as "90 to 10" against. Those odds were improving as the day went on, though, but there was still considerable uncertainty.

There were no such worrying aches and pains for McIlroy as he limbered up for the defence of the crown he won amid such personal tumult last May. On Pro-Am day here at Wentworth 12 months ago, an ashen-faced McIlroy met a salivating media for the first time since he called off his engagement to Caroline Wozniacki. A few days later, he had achieved a cathartic conquest. One year on, and six more victories later, he is almost unstoppable. His seven-shot canter to victory in the Wells Fargo Championship last weekend, a romp that was aided by a rampaging 61 during the third round, must have left his wheezing rivals feeling like they were horse drawn ploughs trying keep pace with that aforementioned Ferrari. It wasn't the first time he had won by such a yawning margin, of course. His first two majors wins, in the 2011 US Open and the 2012 US PGA Championship, were both by eight shots. Importantly, though, McIlroy has developed that ability to grind out a victory, like he did at last year's Open when he staved off the advances of Rickie Fowler and Sergio Garcia, and at the US PGA when Fowler and Phil Mickelson were harrying.

"I've always said I'll take any wins any way I can get them, whether it's by one shot, in a playoff or by seven shots," said the world No 1. "I feel like now I'm a player that can win all different sorts of ways, which I'm happy about. I can be in contention and gut it with a few other players or separate myself from the field, like I did last week."

During his rip-roaring triumph at Quail Hollow over the weekend, McIlroy made the 7,500 yard layout resemble a pitch-and-putt. On his way to that shimmering 61 in round three, the 26-year-old was hitting a 9-iron or less into the greens on 15 of the 18 holes. The only exceptions were on the long par-3s that were all over 200 yards. "He just decimated it with power," said his fellow Northern Irishman, Graeme McDowell, on this display of fearsome explosiveness that is such a huge weapon in the McIlroy armoury.

When he unleashes the heavy artillery, McIlroy is an all-conquering force but he remains wary about the fluctuating fortunes of this Royal & Ancient game. Nevertheless, McIlroy is well aware of his presence among his peers and the growing sense of intimidation he exudes. It may not be on a par with the fear factor that Tiger Woods used to generate in his pomp but McIlroy is getting there. "I don't feel I'm unbeatable, that's for sure," he conceded. "Golf is a very fickle game and it can humble you quite quickly. So I definitely don't think I'm unbeatable. But I do feel that my name carries weight on a leaderboard. Do I feel like I intimidate? I don't know if you'd call it intimidation. But I feel that when players see my name on the leaderboard now, it might mean a little bit more than it used to."

McIlroy was in a laid back mood on the eve of his title defence. On Tuesday night, at the European Tour's awards dinner, he was reaquainted with Sir Alex Ferguson, the Govan great whose words of wisdom to Team Europe during last September's Ryder Cup left a lasting impression on McIlroy. Yesterday, the avid Manchester United fan enjoyed the company of two more former Old Trafford stalwarts, Paul Scholes and Phil Neville, during the Pro-Am. "We had fun but there wasn't much adrenaline in there," he said. "Once I step on to the tee and get a card in my hand on Thursday it will be different."

The rest have been warned.