Joe Root leaves rival in awe as 'scary' comment made after England heroics

England batter Joe Root's insatiable appetite for runs has left even his fellow 'Fab Four' member Kane Williamson in awe.

The pair, plus Australia's Steve Smith and India's Virat Kohli, have lived up to their billing after being banded together and touted as future greats by former New Zealand batter Martin Crowe in 2014.

Root shows no sign of slowing down with 22 hundreds in his last 61 Tests and he recently moved up to second on the list of all-time top run-scorers in the format, now sitting 2,378 behind India's Sachin Tendulkar.

The 34-year-old's prolonged purple patch has so impressed Williamson - the former New Zealand captain - who is no doubt his contemporary seems like he could keep going for a lot longer.

Williamson, who turned 35 on Friday, said: "Joe's just remarkable with what he's doing and where he's going and the things he's ticking off, at the moment. It's incredibly special and great to follow.

"I'm just full of admiration for that. He's a little bit younger than me, which is even scarier, he could keep going and it feels like he could well do for about 20 years!"

While Williamson, Root and Smith continue their Test careers, Kohli, the eldest of the quartet, called time on his career in the longest format earlier this year.

Williamson said: "You never really consider it and you do see some of your opponents and mates making some of these decisions and you think 'gosh, it has been a while', and you're not getting younger.

"It's a reality at some stage. For someone like Virat, who made that decision to go out on his own terms and do what he's done for the game, that's amazing. That's so special.

"Everyone was caught by surprise because you feel like it will never happen, but it does. I'm more aware of that than most - and that's great."

Williamson, with New Zealand's blessing after electing against signing a central contract, has skipped the Black Caps' ongoing Test series in Zimbabwe to play county cricket and The Hundred this summer.

As well as a stint with Middlesex, he is captaining London Spirit, again joining forces with former Australia batter David Warner, an ex-international foe and team-mate at several franchise leagues.

Williamson added: "He's without doubt been one of the greatest in the franchise T20 game. The heights he reached in the Indian Premier League, he's so highly-regarded, he's been one of the all-time greats.

"He's a little bit further down the line in terms of his career but he still has that quality in him and it's great to have him in our team."