"It's fairly frustrating when you have a 22-run start and he beats you to a hundred by 20 balls," sighed Cook, whose own painstakingly compiled century had been rather eclipsed by the seemingly effortless and inevitable feel of Root's sunny ton.
"He makes it look so easy. He is a genius and an unbelievable player to watch from the other end, a lesson to us all." When such a tribute comes from England's record test run scorer, who hails Root as the best batsman he has ever played alongside, then evidently we are talking about the rarest of talents.
Root is still only 26 and has been a test player for only five years but his mastery in this triple-pronged era of tests, ODIs and T20s has been such that he has scored 10,066 runs in all three forms of the international game. Of all the players who have made 10,000-plus in all formats, only Root (50.83) and India's Virat Kohli (53.39) average more than 50.
What is more, he has compiled those runs, including 23 centuries, with such swift facility that it persuades another ex-England captain and fellow Yorkshireman Michael Vaughan to declare: "You can make a case now for saying he's our best ever." From a nation that cherishes names like W.G Grace, Wally Hammond, Jack Hobbs, Denis Compton and Len Hutton, that is some assertion.
Even if some will construe this as hyperbolic, Root still looks a comet with years left to burn. Could it be that the real measure of his greatness may only be starting now as he leads England's Ashes defence? For in his almost uninterrupted triumph of a CV one glaring failure stands out - his lack of success on Australian soil.
No wonder then that there was a sense of a man on a mission when he said at Lord's before flying out with his team: "I'm desperate to go out there and have a better tour than last time." Root has not forgotten how England were terrorised by Mitchell Johnson in that 2013-14 Australian whitewash and how his struggles led to him eventually being dropped for the final test in Sydney.
Yet, strangely, one of the more pleasing memories of that dispiriting tour for English observers was how Root kept smiling back at the growling Johnson while making a defiant 87 in the second test at Adelaide.
It demonstrated the spirit that goes with the skill. Earlier in 2013, Root had famously got under David Warner's skin to such a degree during a chance meeting in a Birmingham pub that the Australian batsman ended up being disciplined for throwing a punch at him.
The incident prompted Root's then Yorkshire captain Andrew Gale to note memorably: "Joe's definitely not a fighter. He couldn't fight his way out of a paper bag. He looks more like the Milky Bar Kid than Mike Tyson."
Yet the angelic appearance was always deceptive. Root worried that after being dropped for that Sydney test. "I didn't know if I'd get another opportunity," he said. As soon as he did the next summer, he took an unbeaten 200 off Sri Lanka.
He has never looked back and has, if anything, batted with even more authority since taking the captaincy this year, his average of 60.75 in his seven matches superior even to his impressive test career average of 53.76.
"I'm obviously a very different player now to what I was last time we were there," Root said. "And that excites me." The idea of the Milky Bar Kid gunning for them on his record-strewn road, however, should continue to exercise the minds of his hosts.
First Published: November 20, 2017, 3:23 PM IST