England's leading Test run-scorer Joe Root still needs an Ashes century in Australia to be considered an "all-time great", according to former Australia head coach Darren Lehmann.
Root has long been branded part of Test cricket's 'Fab Four', alongside Australia's Steve Smith, India's Virat Kohli and New Zealand's Kane Williamson, but has yet to score a century down under.
Root, who averages 51.01 for his 149 Test caps, with 35 Test tons, has a highest score of just 89 over 27 innings in Australia, averaging 35.68.
Lehmann was speaking after Australia were hammered by India in the opening Test of their five-match series in Perth, with Kohli scoring his 30th Test ton and seventh in Australia.
"Nope, he's a rung below for that reason," said Lehmann on ABC Sport, when asked if Root was in the same category as the India batter.
"They've made runs all over the world in difficult conditions against different oppositions, and that's the only thing stopping Joe Root. I think he's a great player, but is he an all-time great?
"I don't have him in that realm. I think you've got to make hundreds all around the world. Smith does, Williamson has, Kohli has, [Rohit] Sharma has - I mean they're world-class players."
England are currently preparing to face New Zealand in a three-Test series starting in Christchurch on Thursday, where Root is set to earn his 150th Test cap.
Responding to Lehmann's comments, Root told BBC Sport: "My job is to score runs, right? To turn up every game and try to do all I can out in the middle. His job is to give his opinion and talk on the radio.
"I'll do my job and he can do his job. He's completely entitled to say what he wants. That's his right."
Sky Sports' Nasser Hussain also weighed in on the debate, giving his backing to Root as England's best-ever batter.
"Root is an all-time great, always will be a great, and will end up an all-time great," Hussain told Sky Sports News.
"Yes, the final piece of the jigsaw is getting runs in Australia. He averages 36 over there, by the way - it hasn't been a nightmare. Sure, he hasn't got a hundred and he'll want to put that right in the next Ashes.
"But just because he hasn't got a hundred in Australia… listen, Shane Warne averaged 43 with the ball in India, and I can tell you, Warne was the greatest bowler I ever faced and arguably the greatest cricketer I've ever seen. Kohli averages 33 in England, but I can tell you, Kohli is a great player.
"Greatness comes over time, from doing it in all conditions, all around the world; 150 Test matches, and Root averages 51. But also, he is so much more than just those statistics. It's the way he plays; he's so pleasing on the eye, the fluidity, the consistency."
After his initial comments, Lehmann later wrote on X: "Just to be clear as there are a lot of people who think that I think Joe Root is not a great.
"He is going to be a great, I know that and a wonderful ambassador for our game, but needs and he will probably do this next Ashes. Get a hundred in Australia and then no dispute."
As well as during previous Ashes battles when Lehmann was in charge of Australia, Root and Lehmann will have crossed paths when Lehmann was an overseas player at Yorkshire until 2006 during the time Root was emerging through the youth ranks.
Lehmann will join county side Northamptonshire as head coach for the 2025 season.
Following their tour of New Zealand, England welcome India for a five-Test series in 2025, with the next Ashes tour of Australia to come during the winter of 2025-26.
England will be looking to regain The Ashes for the first time since 2015. Since their last tour of Australia in 2021/22, Root has been in sparkling form, scoring 12 hundreds and 11 fifties.
"Root has always been bracketed with Williamson, Kohli and Smith, and of late, it's Root who's been really going great guns," former England captain Michael Atherton said on the latest Sky Sports Cricket Podcast.
"Kohli got a hundred in the second innings [in India's first Test win against Australia], but the other three have struggled for one reason or another.
"I guess, for Root, he's got that one little thing still nagging away at him, that failure, or lack of success in Australia, that lack of a hundred in Australia, and that tour is coming down the line.
"I'm sure it's not invading his every waking thought, but I think the great players want to tick off everything in their careers.
"And he's ticked off virtually everything; he's an Ashes winner, more runs than any other England player - he might get up to Sachin Tendulkar [as the world's leading Test run-scorer], who knows? He's brilliant in Asia, and the only place he's not really dominated and done that well is Australia.
"At the end of his career, he'll want to have proven that he can do it there as well, I think, just because that's the last little thing to complete his greatness."
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