The 25-year-old Irishman, looking to add a third major to his collection and a first on British soil, started the day with a four-stroke lead.
But by the time he reached the 12th hole that had vanished and he was caught in a dogfight with American shot-maker Rickie Fowler, hungry to win his first major.
That was when McIlroy, who had been struggling off the tee, produced his best golf of the week at Royal Liverpool.
That gave him a 68 and left him at 16-under for the tournament six strokes clear of Fowler who had eight birdies en route to a 68.
It was the biggest lead at the third-round stage of the Open since Tiger Woods at St Andrews in 2000. Woods eventually won by eight strokes on that occasion.
A further stroke back came Spaniard Sergio Garcia who had a 69 and Dustin Johnson of the United States with a 71. Frenchman Victor Dubuisson was next best on eight under after a 68.
"It is a good thing I have experienced this before, good and bad. Hopefully some of that experience I can take into tomorrow.
"My game plan all week has been to take care of the par fives and I want to do that again tomorrow."
It was already a remarkable day for the British Open because for the first time in its 154-year long history the field went out from both the first and 10th tees instead of just everyone going off the first.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
