Many excellent batters have graced the game but none has been able to match Sachin Tendulkar's longevity.
Tendulkar is the highest run scorer by a fair margin with 15921 runs and an average of 53.78 with 51 centuries and 68 half centuries. The next best is Ricky Ponting who made 13378 runs from 168 test matches at 51.85.
Following Ponting is Jacques Kallis, Rahul Dravid, Kumar Sangakkara, Brian Lara, ShivnarineChandrapaul, MahelaJayawardene, Alan Border and Steve Waugh.
Root made his debut back in 2012 against India at Nagpur and has been going strong since then. Over the last couple of years, he has taken his game to another level and recently became the joint youngest player along with former England captain Alastair Cook to score 10000 runs in test cricket at just 31 years of age.
Root still has a chance of breaking Tendulkar's record if he can keep himself fit and in form over the next 5 years. However, that will be a much tougher job than it seems as there are several players who have flashes of brilliance, even 2-3 years of consistent run making like ViratKohli, Steve Smith, Kane Williamson and Babar Azam but none has been able to match the longevity of the Little Master.
Cook continues to pile on the runs in County cricket but his tank was empty when it came to International cricket. Root, who has already given up captaincy, has also had a lot of mental battering and it will be worthwhile seeing whether he can sustain the rigours of international cricket for much longer.