Not the tempest we expected, but a force of nature all the same.

In the final action of this wet but rarely windy day on Merseyside, Rory McIlroy struck two mighty blows and all but tied up the Open Championship. With eagles at the 16th and 18th holes, he scattered the hopes of his rivals to the four winds and moved six shots clear of the field.

It was a staggering performance and it all but obliterated recollections of the position, little more than an hour earlier, when Rickie Fowler had drawn level with McIlroy with a run of three straight birdies at the start of his back nine. At that point, the big noises around the Hoylake course were all being made by the 25-year-old American, but the roar at the finish, when McIlroy rolled in his final putt, was easily the loudest of the day.

It will surely be echoed this evening when McIlroy finishes the job and wraps up the third leg of his career Grand Slam. This is not the tyro kid who blew a four-shot lead at Augusta three years ago, but an experienced front-runner with two Major titles to his name. Strange things can happen on the last day of this dear old championship, but it is almost inconceivable that McIlroy will not have the Claret Jug in his possession tonight. Just possibly with some bells and whistles attached.

If McIlroy can stretch his third-round lead by a couple of strokes, as he did in winning the 2011 US Open and the USPGA the following year, he will match the highest post-1900 winning margin for the tournament. If he can shoot 66, as he did on each of the first two days here, he will have the record for the lowest winning total, currently held by Greg Norman, who went round Royal St George's in 1993 in 267 shots.

However, it misses the point by some distance to think of his performance purely in terms of numbers: the more significant part of it is that McIlroy is playing with the kind of serenity and self-control that sets him apart from every other player on earth at the moment.

The mind goes back to Tiger Woods in his pomp just over a decade ago. Sergio Garcia spent that period hanging on the coat tails of Woods, and he was pretty much in the same position at Hoylake yesterday, as he carved out a decent-enough round of 69 but still watched the leader gallop off over the horizon. Asked to compare the McIlroy of today with the Woods of back then, Garcia suggested that the American edged the contest on the strength of consistency alone, but as far as the mechanics of the game are concerned, they are pretty much equal.

You would have felt for Garcia and Fowler, who shot a 68, as they made their way down the 17th fairway and heard an almighty explosion of noise behind them. It was the acclaim for McIlroy's first eagle and it told them that their own hopes were suddenly hanging by a thread. In all likelihood, those threads were snapped by the second eagle, at the 18th, around half an hour later.

"I knew that Rickie was playing well in front of me," said McIlroy. "I didn't know how well. But I never panicked. I didn't feel uncomfortable. I knew that I had some holes coming up that I could take advantage of and make some birdies on the way in. I was just very patient today and just waited for my chance, for my time, when I was able to make some shots and I was able to convert them. It was nice to be able to come up with the goods."

"I'm very comfortable. I'm comfortable leading the tournament and this is the third night in a row that I'll sleep on the lead. It helps that I've been in the position before and been able to convert and get the job done. I just need to go out there and play one more solid round and hopefully that will be enough."

Very assured, very Tigerish. Not that the same could be said of the Tiger himself, for after only just squeezing though the cut on Friday the former world number one had another lumpy old day. Woods shot a 73, his card marred by a double bogey at the second and a triple at the third. He has been little more than a spectator here on his return to major action after back surgery.

The pattern of the day also vindicated the R&A's decision to alter the schedule and introduce a two-tee start. Throughout the day there was some grumbling among spectators who complained that there had been an over-reaction to the forecast, but when the heavens opened a few minutes after the close of play the strategy was proven correct. The final day's weather is predicted to be much calmer, and the normal format will return.

And there will, almost certainly, be normal service form McIlroy as well. The faint hopes of players like Fowler, Garcia and Dustin Johnson rest on the possibility that McIlroy will have an early disaster, but there has been nothing in his game or his bearing over the past three days to suggest that is remotely likely. He has given us an exhibition this week. Today we can expect a victory parade.