Root’s 159 runs in his two innings in Dubai were not enough to stop England going 1-0 down with one to play after the second Test against Pakistan.
But the prolific No 4, who with 1,278 has made more Test runs than anyone this year, is back at the top of the table - by just three ranking points from Smith.
The Yorkshireman’s seesaw battle with the new Australia captain for the ICC’s No 1 spot has lasted throughout 2015.
It will be Root, too, who has the next opportunity to further enhance his standing when England face Pakistan again in Sharjah in the final Test on Sunday.
All-time Pakistan Test leading runscorer Younus Khan is also back up in the table, to fifth, after his a century and half-century in Dubai.
Pakistan leg-spinner Yasir Shah took eight wickets in the second Test, a driving force in the hosts’ 178-run win and also a performance which has taken him above England seamers James Anderson and Stuart Broad into second place in the bowlers’ rankings behind only South Africa’s Dale Steyn.