Ricky Ponting insisted there is “absolutely no reason” why Joe Root cannot become Test cricket’s all-time top run-scorer after he was leapfrogged to second on the list by the Yorkshireman.

It was another red-letter day for Root, who eclipsed Rahul Dravid by getting to 30 on the third morning of the fourth Rothesay Test against India before moving ahead of Jacques Kallis with one extra run.

Better was to follow in the afternoon as Root moved serenely to a 38th Test hundred, joint fourth-highest alongside Kumar Sangakkara, and reaching 120 took him past Ponting’s haul of 13,378 runs.

Sachin Tendulkar is way out in front on 15,921 runs but Ponting believes the tally is not beyond reach, pointing out 34-year-old Root’s incredible recent form, which includes 25 centuries since turning 30.

“Congratulations Joe Root,” the former Australia captain said in his role as a pundit for Sky Sports. “A magnificent moment in history. Second on the table. Just the one more to go now.

“About two and a half thousand runs behind, but the way his career’s gone over the last four or five years there’s absolutely no reason why (he cannot be number one).

“You talk about the skill and class of player that Joe Root is, but you can’t ever underestimate the mental capacity side of things as well.

“He still has that hunger and desire to continue to find ways to improve and get better. Trust me, that doesn’t get easier the older you get. Find ways to change your game and improve.

“But he’s made little technical changes to make him a more complete and better Test match batsman.”

In the last year, Root has become England’s most prolific run-scorer in Tests and ODIs, snatching the record from Sir Alastair Cook in the former last October and the latter from Eoin Morgan last month.